Eachunderlinedphrase,

问题详情：

 Each underlined phrase, ______ clicked, provides a drop down menu with a list of choices.

A. that                   B. which               C. when                            D. where

【回答】

C非谓语动词短语作状语表示时间：when we click the phrase / when the phrase is clicked。

知识点：连词

题型：选择题