must be and must have been

[san2612]

1. Jean was working hard all day yesterday; she ………….. very tired
A ought to be B must be C must have been D should have been

In this multiple choice question, I chose B. must be but the answer key is C must have been. Can you tell me which one is correct and why? THankz in advance.

 

[5jj]

1. Jean was working hard all day yesterday; she ………….. very tired
A ought to be B must be C must have been D should have been

In this multiple choice question, I chose B. must be but the answer key is C must have been. Can you tell me which one is correct and why?

A is just about possible; the speaker is suggesting that it is logical to think that she is tired now, though she may not be.
B is possible; if she was working hard all day yesterday, then it is likely that she is tired now.
C is possible, especially if the speaker is thinking "by the end of the day".
D is just about possible; the speaker is suggesting that it is logical to think that she was tired by the end off the day, though she may not have been.

A bad question.

 

[Raymott]

1. Jean was working hard all day yesterday; she ………….. very tired
A ought to be B must be C must have been D should have been

In this multiple choice question, I chose B. must be but the answer key is C must have been. Can you tell me which one is correct and why? THankz in advance.

I would put B. It's common knowledge that if you work very hard all day one day you can be very tired the next day; and this is the most likely interpretation, making B correct.

C is a silly answer. Firstly, one of the interpretations of such a sentence is that she was working hard because she was very tired. Another is that she was very tired after doing the work. If the sentence ended in "afterwards/ after", then C would be possible. If the answer were "must have become" then C would be right too.

B is far more likely than C from a native speaker.

 

[AlexAD]

I'm not a teacher nor a native speaker

At times, I meet questions like that and then I ask myself, 'Who's that guy who made it up?'. May be, just may be, it's better not to use such books replacing them by something that worth reading?