Before entering space rockets must escape _____ the earth’s gravity.
| A．to | B．off | C．of | D．from |
I felt very tired when I got home. and I _______ straight to bed.
| A．go | B．went |
| C．had gone | D．have gone |
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 |