[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"grammar-page-en-that-clauses-and-whether-clauses-as-complements":3,"grammar-exercises-by-page-01a0e1ab-d614-7ce6-bb2b-df1c89246cd8":23,"exercise-list-path-en-none":44},{"id":4,"title":5,"slug":6,"seoDescription":7,"content":8,"language":9,"level":10,"displayOrder":11,"grammarTopics":12,"createdAt":19,"updatedAt":20,"vocabularyLists":21,"readyImages":22},"01a0e1ab-d614-7ce6-bb2b-df1c89246cd8","That-Clauses and Whether-Clauses as Complements","that-clauses-and-whether-clauses-as-complements","Learn to use that-clauses for statements and whether-clauses for yes\u002Fno questions after verbs, adjectives and nouns, with clear word-order rules.","A complement clause completes the meaning of a verb, adjective or noun. Use **that-clauses** to present statements and **whether-clauses** to present yes\u002Fno questions or alternatives. The choice shows whether you are presenting an idea or considering if it is true.\n\n## 1. Statements and open questions\n\nCompare these two sentences:\n\n:::example\n- I know **that the office is open**. → I present this as something I know.\n- I wonder **whether the office is open**. → I am considering the question: Is it open?\n:::\n\nA **that-clause** gives the content of a statement, belief, feeling or claim. It does not necessarily describe a fact:\n\n- Maya believes **that the plan will work**. → This is her belief, not a guarantee.\n- They denied **that they had broken the window**. → This is what they denied.\n\nA **whether-clause** presents a yes\u002Fno question or a choice between alternatives. It does not always mean that the speaker is uncertain:\n\n- I don't know **whether Sam is coming**. → I do not have the answer.\n- I know **whether Sam is coming**, but I can't tell you. → I have the answer, but I do not give it.\n\n## 2. Form and word order\n\nBoth types normally use **subject + verb** order, even when a whether-clause represents a question.\n\n| Clause type | Structure | Example |\n| --- | --- | --- |\n| Statement content | that + subject + verb | She explained **that the train was delayed**. |\n| Yes\u002Fno question content | whether + subject + verb | She asked **whether the train was delayed**. |\n| Negative statement content | that + subject + negative verb | I think **that he doesn't agree**. |\n| Negative question content | whether + subject + negative verb | I wonder **whether he hasn't seen the message**. |\n\nCompare a direct question with a complement clause:\n\n:::example\n**Direct question:** Does Leo need help?\n\n**Complement:** I wonder **whether Leo needs help**.\n\n**Direct question:** Is the door locked?\n\n**Complement:** Can you check **whether the door is locked**?\n:::\n\nThe second complement appears inside a question, but its own word order remains **the door is**, not **is the door**. The question mark belongs to the whole question.\n\n:::warning\nDo not use question word order or question-forming **do\u002Fdoes\u002Fdid** inside a whether-clause.\n\n✗ I wonder whether does Leo need help.\n\n✓ I wonder **whether Leo needs help**.\n\nNegative **do** is different and can remain: I wonder **whether Leo doesn't want help**.\n:::\n\n## 3. Complements after different words\n\nComplement clauses can follow verbs, adjectives and nouns. The word before the clause affects which type is possible.\n\n| Position | That-clause | Whether-clause |\n| --- | --- | --- |\n| After a verb | We believe **that the figures are correct**. | We discussed **whether the figures were correct**. |\n| After an adjective | I'm pleased **that you can come**. | I'm unsure **whether you can come**. |\n| After a noun | The claim **that the product is safe** needs evidence. | The question of **whether the product is safe** remains unanswered. |\n| After the linking verb *be* | The problem is **that we have no money**. | The question is **whether we can afford it**. |\n\nWith **question** and **issue**, **of whether** is a common pattern: **the question of whether it is safe**, **the issue of whether we should proceed**. **The question whether** is also possible, especially in formal writing. With **doubt**, use **doubt about whether** or **doubt as to whether**: **There is some doubt about whether it will work**.\n\nUseful patterns include:\n\n- **think, believe, say, explain + that-clause**;\n- **ask, wonder, discuss + whether-clause**;\n- **certain, pleased, aware + that-clause**;\n- **unsure, uncertain + whether-clause**.\n\nOther common B2 patterns are:\n\n| Pattern | Example |\n| --- | --- |\n| suggest + that | The evidence suggests **that the figures are wrong**. |\n| realise + that | I realised **that I had left my keys at home**. |\n| admit + that | She admitted **that she had made a mistake**. |\n| decide + whether | We must decide **whether we can afford the trip**. |\n| find out + whether | Please find out **whether the tickets are still available**. |\n| doubt + whether | I doubt **whether we have enough time**. |\n| doubtful + whether | It's doubtful **whether the repairs will be finished today**. |\n| not sure + whether | I'm not sure **whether this is the right address**. |\n\nSome words allow both, with a difference in meaning:\n\n:::example\n**Check that the door is locked.** → Make sure it is locked.\n\n**Check whether the door is locked.** → Find out if it is locked or not.\n:::\n\nDo not assume that every verb accepts both patterns. For an open question, say **I wonder whether she agrees**, not *I wonder that she agrees*.\n\n### Noun complements and relative clauses\n\nCompare these two noun phrases:\n\n- **the claim that the product is safe** → The clause gives the content of the claim. **The product is safe** is a complete statement.\n- **the claim that the company made** → The relative clause identifies the claim. The company made **the claim**, so **that** represents the object of **made**.\n\nOnly the relative clause allows **which** here: **the claim which the company made**. Because **that** is the object in this relative clause, you can also omit it: **the claim the company made**.\n\nIn a noun complement, **that** introduces the content and cannot be replaced by **which**. Keep it in **the claim that the product is safe** for clarity. Some noun complements allow omission, especially informally, so omission alone is not a reliable test for a relative clause.\n\n## 4. When you can leave out that\n\nAfter many common verbs, **that** is optional, especially in conversation:\n\n- I think **that you're right**. → I think **you're right**.\n- She said **that she was tired**. → She said **she was tired**.\n\nIt is also often omitted after common adjectives:\n\n- I'm glad **that you're here**. → I'm glad **you're here**.\n\nKeep **that** when it makes a long sentence easier to follow. In formal writing, it is often helpful after nouns: **the claim that the product is safe**.\n\n:::note\nYou cannot simply omit **whether** in the same way.\n\n**I don't know whether she's coming** leaves the question open.\n\n**I don't know she's coming** does not express the same meaning; without further context, it also sounds unusual.\n:::\n\n## 5. Whether, if and alternatives\n\nAfter many verbs, **if** can replace **whether** when introducing a yes\u002Fno question. **Whether** is often preferred in formal writing.\n\n- I don't know **whether the shop is open**.\n- I don't know **if the shop is open**.\n\nHowever, they are not interchangeable in every structure.\n\n| Context | Pattern to use | Example |\n| --- | --- | --- |\n| After a preposition | whether | It depends on **whether we have time**. |\n| Immediately before *or not* | whether or not | I don't know **whether or not she agrees**. |\n| After a verb, including with *or not* at the end | whether or if when the verb allows both; use whether after discuss and consider in standard edited English | I don't know **if she agrees or not**. We discussed **whether we should stay or not**. We considered **whether we should leave**. |\n| Before an infinitive | whether to | We haven't decided **whether to stay**. |\n\nFor two explicit alternatives, **whether … or …** makes the choice clear:\n\n:::example\nWe need to decide **whether to travel by train or by bus**.\n\nThe question is **whether we should leave today or wait until tomorrow**.\n:::\n\n:::tip\nAfter a preposition, use **whether** for a question. For statement content, you often need a noun before **that**:\n\n- We talked about **whether the plan would work**.\n- We talked about **the fact that the plan had failed**.\n\nDo not write *about that the plan had failed*.\n:::\n\n## 6. Clauses as subjects and extraposition\n\nThat-clauses and whether-clauses can also act as the subject of a sentence:\n\n- **That he lied** is obvious. → The fact that he lied is obvious.\n- **Whether he comes** doesn't matter. → His coming or not coming makes no difference.\n\nKeep **that** when a that-clause is the subject before the main verb. For a yes\u002Fno clause in this position, use **whether**, not **if**:\n\n✗ If he comes doesn't matter.\n\n✓ **Whether he comes** doesn't matter.\n\nIt is often more natural to begin with **it** and put the clause later, especially when the clause is long. This pattern is called **extraposition**. Here, **it** fills the subject position without referring to a particular thing.\n\n| Clause as subject | Extraposition with it |\n| --- | --- |\n| **That the plan failed** is clear. | It is clear **that the plan failed**. |\n| **Whether they will agree** is unclear. | It's unclear **whether they will agree**. |\n| **That he lied** is obvious. | It is obvious **that he lied**. |\n| **Whether he comes** doesn't matter. | It doesn't matter **whether he comes**. |\n\nThe restriction on **if** applies to a subject clause before the main verb. After introductory **it**, **if** is possible in some patterns: **It's unclear if they will agree**. **Whether** works in both positions.\n\n## 7. Quick decision checklist\n\n1. Are you presenting a statement, belief or claim? Choose **that**: I believe **that it's possible**.\n2. Are you presenting a yes\u002Fno question or alternatives? Choose **whether**: I wonder **whether it's possible**.\n3. Check the preceding word: **believe that**, but **wonder whether**.\n4. Use **subject + verb** order inside the clause.\n5. Omit **that** only where the pattern allows it; do not omit **whether**.\n6. After a preposition or before **to + verb**, choose **whether**, not **if**.","en","B2",90.55,[13],{"id":14,"name":15,"level":10,"language":9,"isCompleted":16,"completionPercentage":17,"totalExercises":18,"completedExercises":17},"01a0e1ab-d4ec-7155-95ae-83a9fed5d465","Content clauses and complements",false,0,2,"2026-09-27T07:02:10+00:00","2026-10-14T10:40:29+00:00",[],[],[24,35],{"@id":25,"@type":26,"id":27,"grammarPage":28,"title":29,"instructions":30,"displayOrder":17,"type":31,"questionCount":32,"blankCount":33,"isCompleted":16,"ogImageUrl":34},"\u002Fapi\u002Fgrammar_exercises\u002F01a0e1ab-e001-76e1-a32c-ef3973b9bc0d","GrammarExercise","01a0e1ab-e001-76e1-a32c-ef3973b9bc0d","\u002Fapi\u002Fgrammar_pages\u002F01a0e1ab-d614-7ce6-bb2b-df1c89246cd8","That-Clauses and Whether-Clauses as Complements — Forms in Context","Choose the option that completes each sentence in context. Where an option contains a slash, both alternatives must fit.","word_select",15,21,"\u002Fuploads\u002Fimages\u002Fgpimg_4e5bd3b5-7d5b-4469-af75-b96f5e40e96c_hero.webp?v=1790492532",{"@id":36,"@type":26,"id":37,"grammarPage":28,"title":38,"instructions":39,"displayOrder":40,"type":41,"questionCount":42,"blankCount":42,"isCompleted":16,"ogImageUrl":43},"\u002Fapi\u002Fgrammar_exercises\u002F01a0e1ab-e029-7d54-8fd0-383064201d56","01a0e1ab-e029-7d54-8fd0-383064201d56","That-Clauses and Whether-Clauses as Complements — Build the Sentences","Arrange the word tiles to build each sentence. Leave out the extra word.",1,"sentence_builder",12,"\u002Fuploads\u002Fimages\u002Fgpimg_af0b21d2-fa88-4dfa-bfc4-db102b453dcd_hero.webp?v=1790492532",null]