This house is quite old. It ________ over 100 years ago.
A. is built
B. were built
C. was built
D. built
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.