E-22换热面积是()m2。
A、102
B、137
C、200
D、182
参考答案:B
计算
,其中D是由x2+y2=4与x2+(y+1)2=1围成的区域.
The old woman has _______________ too many hardships in the past 10 years.
A.broken through
B.gone on
C.broken down
D.gone through