After he _______ in a factory he opened a small business.
A. has worked
B. had worked
C. would work
D. was working
Đáp án B
I think we should have our house painting because it looks too dirty.
The situation is serious. Something must ___________ before it’s too late.
Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following question.
Species that have already lost habitat because of deforestation were given higher priority in the plan because of their greater risk of extinction.