Question

【题目】 ______ the average age of the population increases, there are more and more old people to care for.

A. Unless B. Until

C. As D. While

Answer 1

【答案】C

【解析】试题分析：句意：随着人口平均年龄的增长，越来越多的老人要照顾。Unless除非；until直到；as因为，正如，随着；while虽然，然而，当……时候。根据语境，故选C。