在以北极为中心的地图上,地球呈逆时针自转。[ ]
√
To _____, in the school art festival next week, the quiet boy will have an opportunity to attract public attention.
A.our credit
B.his delight
C.his astonishment
D.his credit
循环系统的关键设备是(),通常称之为钻机的心脏。
A.钻井泵
B.转盘
C.水龙头
D.绞车