Children who are over-protected by their parents may become _____.

A．hurt

B．spoiled

C．damaged

D．harmed

一起重机用长4m的钢丝绳吊一重为2000kg的重物，以2m/s的速度在水平方向上匀速行驶，当起重机突然停住的瞬间，钢丝绳受到的拉力是______N．         （取g=10m/s²）