________, I think, and the problems could be settled.
| A．If you double your efforts |
| B．So long as you keep up your spirits |
| C．Making greater efforts |
| D．A bit more efforts |
The population of Africa is __________ so rapidly as to cause great concern of the whole world.
| A．expanding | B．stretching | C．extending | D．spreading |
Living with a host family while studying abroad, in which there may be some other college students, __________ you the chance to learn more about the new culture.
| A．give | B．gives | C．giving | D．to give |
Only after Li Qi focused on his strengths instead of his weakness ___________ himself from his inferiority complex（自卑感）.
| A．he freed | B．he had freed | C．did he free | D．had he freed |
In Singapore, people who litter or dirty the street are most likely ___________.
| A．to fine | B．fined | C．to be fined | D．being fined |
Joseph __________to evening classes since last month, but he still can’t say “What’s your name?” in Russian.
| A．has been going | B．went | C．goes | D．has gone |