About ____ gene-targeting drugs are already in testing pipeline. It won’t be long ____ they are put into effect.

A．two dozen; before

B．two dozens; that

C．two dozens of; before

D．dozens; that

新石器时代中晚期即相传中的（）时期开始有了纺织而成的衣料，皇帝、尧、舜时代已有了成型的衣服。

A.女娲

B.神农

C.伏羲

D.后羿