giúp
----- Nội dung dịch tự động từ ảnh -----
46
"Could you turn off the stove? The potatoes --- for at least thirty minutes."
A. are boiling
C. have been boiling
B. were boiling
D. boiled
47
Carbon dioxide - as one of the main contributors to the greenhouse effect.
A. has been identified
C. had identified
B. has identified
D. had been identified
48
The headmaster has decided that three lecture halls ----------- in our school next semester.
A. will build
C. are being built
B. will be build
D. will be building
49
Although MERS spreads through close contact with sick people, not through the air, many people still avoid -- to crowded places.
A. to go
C. gone
B. having gone
D. going
50
Students will not be allowed into the exam room if they ---- their student cards.
A. produced
C. didn't produce
B. hadn't produced
D. don't produce