用方框中所给单词或短语的适当形式填空。每词仅用一次。

throw away；divide；repeat；plastic；rapid

【1】The teacher ________ the class into small groups.

【2】Waste paper mustn't _________. We should keep our environment clean.

【3】It's unbelievable that technology has progressed in such a ________ way!

【4】Mr. Wu is really a good teacher. He spends as much time as he can ________ grammar rules for us.

【5】The pair of sunglasses is made of ________.