临时补修是为保持轨道具有一定的(),而进行的临时性修理。
A、强度
B、储备能力
C、承载能力
D、平顺性和整体性
参考答案:D
After going into the concert hall, the mother ________ a friend and went over to greet him.
A.searched
B.knew
C.realized
D.spotted
计算题:一台十级离心泵,当入口压力P1=0.21Mpa,出口压力为P2=6.5Mpa,入口水温t=109.32℃,求该泵的总扬程和单级扬程是多少。(已知该温度及入口压力下,饱和水密度P=951.2kg/m3,g=9.81m/s2)