Question

【题目】You must keep on working in the evening, you are sure you can finish the task in time.

A. as

B. if

C. when

D. unless

Answer 1

【答案】D

【解析】本题考查连词的用法。句意为：你必须在晚上继续工作, 除非你确信会按时完成任务。unless引导一个状语从句, 意思同if...not...，符合句意，为正确选项。