Bears ______ fat stores throughout the summer and fall to have energy enough to last them through their winter sleep.
| A．bring up | B．pack up | C．take up | D．build up |
You will fall in love with that city _____ you learn about it.
| A．since | B．while |
C．before | D．once |
Many websites have been _______ to help people study foreign languages.
| A．set off | B．set up |
C．set down | D．set out |
This is the deepest swimming pool _______ I have ever seen in China.
| A．that | B．what |
C．where | D．Which |
Kathy told me that all the doors and windows _______ when she arrived this morning.
| A．have cleaned | B．have been cleaned |
C．had cleaned | D．had been cleaned |
It was in the forest _______they found the lost cow.
| A．where | B．when |
| C．that | D．as |