不准用总离合器代替滚筒离合器，离合器不准在（）状态使用.
参考答案：半离合
Which of the following is NOT true of meditation
A．It relieves the pain of cancer.
B．It counteracts the effect of depression.
C．It has mystic elements.
D．It has long been used as a cure-all.
李凡同学的质量为50kg，他站在地面上时对地面的压力为______N；浸入足够深的水中时，受到的浮力是______N．（ρ人=ρ水=1.0×103kg/m3，g=10N/kg）
