Due to the unreasonable individual income __________，the gap between the rich and poor has become an outstanding issue.
| A．contribution | B．association |
| C．accommodation | D．distribution |
As long as you stick to it,you’ll make progress ________.
| A．in time | B．at a time | C．at one time | D．on time |
The two balls fell ________the same speed and landed ________the ground at the same time.
| A．off;on | B．by;in | C．with;on | D．at;on |
After many years of hard work,Mary and her husband had at last paid ________all the money they had borrowed.
| A．for | B．out | C．in | D．off |
They thought the meeting was ________great importance.
| A．in | B．for | C．of | D．/ |
________the birthrate down by 10%,the number of the population has decreased.
| A．For | B．With | C．As | D．By |