Parents should pay attention to areas _______ their child is having difficulty and spend extra time to help him or her master those skills.
| A．as | B．where | C．why | D．when |
We must __________ that the experiment is controlled as rigidly as possible.
| A．propose | B．secure | C．ensure | D．Issue |
The bank has _________ some property on which to constructed.
| A．paid | B．picked up | C．purchased | D．Invested |
The island in the middle of the lake _____________ the beauty of the lake.
| A．adds up to | B．adds to | C．adds up | D．adds |
It is important for us to employ a word or phrase according to the ________ in language studies.
| A．situation | B．expression | C．comprehension | D．Translation |
The boy will make a lot of trouble when ____________ alone.
| A．leaving | B．leave | C．left | D．being left |