一．People are recycling many things which they away in the past.
A. had thrown B. will be throwing
C. were throwing D. would have thrown
【考点】考察情态动词用法
【答案】D
【解析】句义：人们作者回收利用他们过去常常会扔掉的东西。Would have done过去常常做某事；是对过去发生的事情的推测。如果不适应情态动词，可以使用一般过去时threw。故D正确。
【举一反三】I ______ sooner but I didn’t know that they were waiting for me.
A. had come B. was coming C. would come D. would have come
【答案】D
【考点】考查虚拟语气的用法。
【解析】句意为“我本来可以早点来，但我真不知道他们在等我。”but I didn’t know表示了过去时间，因此前句是对过去的虚拟，用主语+should / would / could / might + have done表达，故选D。
