Question

Complete the following conversation with a suitable option:
Adam: 'I'm going out now'.
Evan: 'OK. What time do you think __________________?

• A. will you be back
• B. have you been back
  
• C. you will be back
  
• D. you have been back
  

Answer 1

Answer: (C)

you will be back

Options A and C:
In the interrogative sentence, the main structure is 'What time do you think + object', where the clause that follows 'you will be back' is the object of the verb 'think'.
Hence, the dependent clause 'you will be back' does not follow inversion, ('inversion' means the subject comes after the verb, and is used in questions). As the clause does not need inversion as seen in 'will you be back', option C is correct and A is incorrect.
Option B: 'Have you been back' refers to an action that has just happened (present perfect tense). But, as mentioned in the first line 'I'm going out now', the action of 'being back' can only happen in the future.
Option D: Similarly, 'you have been back' is also in the same tense. (The only difference is that in B, the words 'have you been back' are of the interrogative form and in D, 'you have been back' is in statement form.)
Hence options B and D are incorrect.