造成水连通管不通的可能性有()、水连通关内有异物堵塞等原因。
A. 放水阀故障
B. 冲洗水位计时,操作不当,使水连通管内自锁装置动作而没有回位
C. 水侧考克操作方向错误
D. 汽侧快关阀操作方向错误
The sealing function of the piston ring is brought about by the gas pressure above and behind the piston ring, which forces it () against the bottom of the ring groove, and () against the cylinder wall.
A. upwards;inwards
B. upwards;outwards
C. downwards;inwards
D. downwards;outward
铣削不锈钢时,铣刀耐用度在()分钟是允许的。
A. 160
B. 170
C. 180
D. 100
丹尼尔·笛福是英国现实主义小说的奠基人,代表作是()。