Scientists say it may be five or ten years ______ it is possible to test this me

游客2023-11-13 43

问题 Scientists say it may be five or ten years ______ it is possible to test this medicine on human patients.

选项 A、since
B、when
C、after
D、before

答案 D

解析 before作从属连词，引导状语从句，意为“到……之前”，如：It was some time before I realized the truth．过了很长一段时间我才了解到真相。

转载请注明原文地址:http://tihaiku.com/zcyy/3184085.html

相关试题推荐

随机试题

最新回复(0)

Thebankmanageraskedhisassistantifitwaspossibleforhimto______thein