Great changes _____ in China in the past 30 years and many Chinese are living a happy life today.
| A．took place | B．were taken place |
| C．have taken place | D．have been taken place |
People who do not smoke have less ______of suffering from lung cancer than those who do so．
| A．potential | B．pattern |
| C．preference | D．prejudice |
This factory produced much dirty water, which resulted in a wide______of environmental problems．
| A．branch | B．range |
| C．species | D．wave |
Please tell me how the accident _______．I am still in the dark．
| A．came up | B．came out |
| C．came to | D．came about |
It is______ of him to set his aim high but do little, so he is always leaving things undone．
| A．specific | B．typical |
| C．flexible | D．widespread |
— Do you think it's a good idea to make friends with your students？
—________, I do．I think it's a great idea．
| A．Really | B．Hopefully |
| C．Actually | D．Eventually |