---John and Tom, you two clean the classroom today, _____?
---But we cleaned it yesterday.
| A．do you | B．will you | C．didn’t you | D．don’t you |
You have to explain ____ us the reason _____ your being absent from school yesterday.
| A．to; of | B．to; why | C．for; that | D．to; for |
There are two thousand students in this college, ______ are from the countryside.
| A．one-third of them | B．one-third of which |
| C．one-third of whom | D．one-third in which |
---How can you keep slim as a mother of two sons?
---I _______ in the gym for years.
| A．have worked out | B．have been working out |
| C．have worked on | D．have been working on |
In the past ten years, the ____mountain climber ____ a lot from his own adventurous _______
| A．experienced; experienced; experience | B．experience; experienced; experiences |
| C．experienced; has experienced; experiences | D．experience; has experience; experience |
The average temperature this year is _______ that of last year.
| A．as not high as | B．not as high | C．not as higher as | D．not as high as |