什么因子会使气团变性？
参考答案：
1、下垫面性质差异；
2、离开源地时间长短；
3、空气运动状态变化。
闸门止水橡皮破坏通常有四种情况，（）不属于其中之一。
A、老化
B、磨损
C、撕裂
D、漏水
His first baby was born soon after he got married, which seemed to have _____ his sense of responsibility.
A．brought down
B．brought out
C．brought about
D．brought in
