Years ago we didn’t know this, but recent science ____ that people who don’t sleep well soon get ill.
A. showed
B. has shown
C. will show
D. is showing
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John told Mary that he ____ what he was doing during the holiday.
A. had just been asked
B. has just asked
C. was just asked
D. just asked
I will tell him the good news when he ____ back to the company tomorrow.
A. comes
B. came
C. has come
D. had come
Is this the first or the second time that you ____ the safari park?
A. had visited
B. have visited
C. visited
D. visiting
By the end of July, I ____ in the lab for seven months.
A. would have been working
B. have worked
C. will have worked
D. will have been working
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