第 1 题 · 四级
The books are bound together with a strong thread, which keeps them safe.
核心词：bind baɪnd v. 捆绑，装订
书用结实的线装订在一起，让它们保持完好。
一般现在时被动语态 + bind together + which 从句短语 bind together短语 bind up
The books are ___ together with a strong thread, which keeps them safe.
第 2 题 · 四级
The core of the problem is money, which the manager has to solve first.
核心词：core kɔː n. 核心，果心
问题的核心是钱，经理必须先解决。
一般现在时主系表 + which 从句 + have to do短语 the core of短语 core value
The ___ of the problem is money, which the manager has to solve first.
第 3 题 · 四级
The artist painted on canvas, which he had bought from the old shop.
核心词：canvas ˈkænvəs n. 帆布，画布
画家在帆布上作画，那是他从老店买的。
过去完成时paint on + which 从句（过去完成）短语 paint on canvas短语 a canvas bag
The artist painted on ___, which he had bought from the old shop.
