第 1 题 · 四级
The store sent us a new catalog, which lists all the products for sale.
核心词：catalog ˈkætəlɒg n. 目录
商店给我们寄了新目录，列出了所有在售商品。
一般过去时send sb sth + which 从句 + for sale短语 a product catalog短语 a card catalog
The store sent us a new ___, which lists all the products for sale.
第 2 题 · 四级
The earth is not a perfect sphere, which scientists have proved long ago.
核心词：sphere sfɪə n. 球体；范围
地球不是完美的球体，科学家很久以前就证明了。
现在完成时主系表否定 + which 从句（现在完成）短语 a perfect sphere短语 the sphere of
The earth is not a perfect ___, which scientists have proved long ago.
第 3 题 · 四级
He found himself in the midst of a crowd, which made it hard to move.
核心词：midst mɪdst n. 中间，当中
他发现自己身处人群之中，很难移动。
一般过去时find oneself in + in the midst of + which 从句短语 in the midst of短语 in our midst
He found himself in the ___ of a crowd, which made it hard to move.
