题目
词汇与语法结合题:根据中文提示及句意,用本单元核心词汇的正确被动形式补全句子。1. Rubbish must not ________ (扔,throw) into the river. 2. Air ________ (污染,pollute) badly in this city since the factory was built. 3. More trees will ________ (种植,plant) around the school next year.