--- I visited a middle school in Shanghai last month.
---There were about six _____________ students in it.
A. thousands
B. thousands of
C. thousand
I eat five meals a day. I have _____ 5 pounds.
A. put on B. put up C. put in
Our classroom must______every day.
A. clean B. be cleaned C. is cleaned
The boy always makes _______ cry.
A. she B. her C. hers
Tea was invented by _______ accident.
A. an B. the C. ＼
Haze weather has become common in some major cities in China. We all wonder ________.
| A．how is the air polluted |
| B．what can we do with the bad weather |
| C．why the air is polluted seriously |
| D．what are the real reasons |