Question

【题目】The volunteers kept their hands in hot water __________ they could no longer tolerate the pain.

A. unless B. until

C. when D. after

Answer 1

【答案】B

【解析】A.unless除非；B.until直到；C.when 什么时候；D. After在…后；句意：志愿者们把他们的手放在热水直到他们不再忍受疼痛。故选B。