Do you know when Britain ______war on Germany during the Second World War?—In 1993，I suppose.

He is taller than__________student in his class .He is the tallest one.

We haven’t settled the problem of_______it is necessary for him to study abroad.

在下列句子的空缺处依次填入词语，最恰当的一组是（ ）①掐丝是一种非常 的工作。②这篇论文写得精准透彻，主要得力于作者 了大量资料。③人类对大自然的每一分破坏，都遭到了相应的报复，环境污染的威胁不亚于第三次世界大战，这绝不可 。

It’s reported that there is ________ big breakthrough in the cancer treatment—If only my wife could be brought back to ________ life