—How many students are there in your school?

—About _____. And one third of them _____ girls.

A. two thousand; is                  

B. two thousands; is

C. two thousand; are                  

D. two thousands; are

以下原则与苏格拉底“产婆术”的实质一致的是（）

A.启发性原则

B.循序渐进原则

C.因材施教原则

D.系统性原则