Question

【题目】This hole is so small that only one person can pass it ________.

A. in timeB. on timeC. at a timeD. for a time

Answer 1

【答案】C

【解析】

句意：这个洞太小了，一次只能有一个人通过。A. in time及时；B. on time按时；C. at a time依次， 逐一；D. for a time一段时间。这里是是说一次，依次。根据题意，故选C。