对攻防因素较多的动作可采用（）教学法。

自春秋战国以来持续数百年的诸侯割据局面结束的标志是

A．秦灭六国，完成统一

B．蒙恬北击匈奴，夺回河套

C．秦始皇自称始皇帝

D．秦朝郡县制度的实施

______ their house in London, they also have a villa in Spain.

A．More than

B．Apart from

C．As well as

D．In terms of

______ him well, I would have invited him to my birthday party.

A．Had I known

B．Should I know

C．If I know

D．If I knew

签发空头支票或者签发与其预留的签章不符的支票，持票人有权要求出票人赔偿支票金额（）的赔偿金。

A.1%

B.2%

C.5%

D.10%

巢式PCR与普通PCR相比（）。

A．普通PCR比巢式PCR敏感

B．所用酶不同

C．所用底物不同

D．模板不同

E．前者用两对引物，后者用一对引物