Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blank 31.
A. twenty
B. twenties
C. twentieth
D. twentyth
Đáp án C
I think we should have our house painting because it looks too dirty.
The situation is serious. Something must ___________ before it’s too late.
Species that have already lost habitat because of deforestation were given higher priority in the plan because of their greater risk of extinction.