My father warned megoing to the West Coast because it was crowded with tourists.
| A． | by | B． | on | C． | for | D． | against |
Nowadays, many people walk to work ________ Copenhagen Conference calling for living a low-carbon lifestyle to cope with global warming.
| A．in response to | B．in relation to |
| C．in addition to | D．in opposition to |
Helen alway s helps her mother even though going to school _____ most of her day.
| A．puts up | B．makes up |
| C．saves up | D．takes up |
During the last three decades, the number of people participating in physical fitness programs ________ sharply.
| A．was increasing | B．has increased |
| C．had increased | D．will be increasing |
You can imagine the difficulty they have ________ such a large population.
| A．fed | B．to feed |
| C．feeding | D．been fed |
____ apple fell from the tree and hit him on ______ head.
| A．An; the | B．The; the |
| C．An; 不填 | D．The; 不填 |