You see the lightning it happens, but you hear the thunder later. A. the instant

 You see the lightning _______ it happens, but you hear the thunder later.

A. the instant                                                   B. for an instant

C. on the instant                                               D. in an instant

试题答案

解析：选A。考查the instant 引导的时间状语从句。句意：一打闪，你就能看到闪电，但是之后你才听到雷声。the instant 一……就……，引导时间状语从句，其他的短语都不能引导时间状语从句。