简述流量脉动的含意。
参考答案:
泵的流量按一定规律不断变化,时大时小。
I will never forget ____ to country village to see the poor children of my age.
A.to take
B.to be taken
C.taking
D.being taken
软件开发环境是全面支持软件开发全过程的【 】集合。