发电机一变压器组递升加压开机时主变中性点刀闸应（）。
A.投入
B.拉开
C.与中性点无关
参考答案：A
如图所示，矩形ABCD的面积为1，E、F、G、H分别为四条边的中点，FI的长度是IE的两倍，问阴影部分的面积为多少（）
A．
B．
C．
D．
The city ________ 6 billion yuan to preserve the character of the old town, mainly to divert water from the Taihu Lake and the Yangtze River to supply the waterway systems of the old town.
A．invested
B．proved
C．invaded
D．invented
