单选题 15. The economy of Colonia has been in recession for the past eight years. Most companies that have not been forced into bankruptcy have survived thanks to the high efficiency of the employees they retained, which helped the companies control costs. In recent months, however, the Colonian economy has begun to recover, and companies are beginning to expand their workforces. Colonia, therefore, will soon experience a drop in average worker efficiency, since ______.
Which of the following, if true, most logically complete the argument? ______

A、 people who have been employed throughout the recession will, no doubt, continue to be employed
B、 Colonia is expected to begin importing more goods from other countries
C、 most companies will find that few of the workers available for hiring are as efficient as those they retained during the recession.
D、 during the recession, workers did not receive any raise in their pay.
E、 many companies that were forced into bankruptcy in the past eight years had a fair number of efficient workers.

【正确答案】 C

【答案解析】 C：该选项说明能够雇佣的新员工效率不如之前被留下来的员工，因此稀释了平均工作效率，正确。
A：衰落期被雇佣的工人很高效，他们继续被雇佣，无法说明为什么工人的平均效率会下降，不选。
B：工人效率和进口商品没有关系，不选。
D：根据本文，工作效率和工资上涨没有关系，不选。
E：该选项重复原文，不选。