风筒修理室内需配备(),做好防火工作。
A、取暖器材
B、灭火器材
C、阻燃器材
D、通风设备
参考答案:B
—Which of the two T-shirts will you take?
—I'll take _____, one for my brother, the other for my-self. [ ]
A. either
B. neither
C. all
D. both
刘明在0.5min内,用20N的水平推力使重120N的超市购物车在水平路面上前进了15m,在此过程中他做的功是______J,功率是______W,购物车重力做的功是______J.