第 1 题 · 四级
The notice must be put in a conspicuous place, which the staff have been reminded of.
核心词：conspicuous kənˈspɪkjuəs adj. 显著的，显眼的
通知必须贴在显眼处，员工们已被提醒过。
现在完成时情态被动 must be put + which 从句（现在完成被动）短语 a conspicuous place短语 conspicuous consumption
The notice must be put in a ___ place, which the staff have been reminded of.
第 2 题 · 四级
The sound was amplified by the microphone, which the singer could be heard clearly.
核心词：amplify ˈæmplɪfaɪ v. 放大，增强
声音被麦克风放大，歌手的演唱清晰可闻。
一般过去时被动语态 was amplified + which 从句（情态被动）短语 amplify sound短语 amplify the signal
The sound was ___ by the microphone, which the singer could be heard clearly.
第 3 题 · 四级
The audience was attentive during the lecture, which the speaker appreciated very much.
核心词：attentive əˈtentɪv adj. 注意的，留意的
演讲期间听众聚精会神，演讲者非常感激。
一般过去时主系表 + 介词短语 + which 从句短语 an attentive audience短语 be attentive to
The audience was ___ during the lecture, which the speaker appreciated very much.
