—So many problems! I’m tired.

—You should try to        them by yourself. You are not a child any longer.

A．get into

B．get off

C．get on

D．get over

某同学提着重60N的书包在水平路面上行走了60m的路程，他在这个过程中对书包做了______J的功，后来他又提着书包以1m/s的速度登上15m高的5楼，他在上楼过程中对书包做了______J的功，功率为______W．