已知某钢筋混凝土框架柱，截面尺寸b×h=300mm×400mm，柱净高H0=3m，混

（）用饱和KSCN溶液可同时检验Fe³⁺和Co²⁺。

Part of the reason Charles Dickens loved his own novel, David Copperfield, was ________ it was rather closely modeled on his own life.(2010·北京)

A．what

B．that

C．why

D．whether

It is well known to us all ____ China sent up a manned spaceship to outer space

Successfully last year.

A．that

B．what

C．which

D．when

变压器分级绝缘指靠近中性点主绝缘水平比绕组端部的绝缘水平高。（）

试验车的基本编码是（）。

A.WJ

B.SY

C.WS

D.YZ