高压严密性试验应在液压强度试验合格后进行，以空气试验时，其压力不宜超过（）公斤力/厘米2。
A.350
B.250
C.300
参考答案：B
When travelling in America, we stayed in a quiet hotel, __________.
A．next to it was a thick wood
B．next to which was a thick wood.
C．next to it there was a thick wood
D．next to which a thick wood was
下列平原中，由侵蚀作用形成的是（）
A.东欧平原
B.亚马孙平原
C.密西西比平原
D.印度河--恒河平原
