用图甲、乙两种方式匀速提升重为100N的物体,已知滑轮重20N、绳重和摩擦力不计。则( )
A:手的拉力:F甲=F乙;机械效率:η甲=η乙
B:手的拉力:F甲<F乙;机械效率:η甲<η乙
C:手的拉力:F甲>F乙;机械效率:η甲<η乙
D:手的拉力:F甲>F乙;机械效率:η甲>η乙
(____)He wants to play baseball.
(____)Tim was so happy because he got a gift.
(____)Why are you wearing a Tshirt?
(____)I am going to the cinema tomorrow.
(____)It's difficult to fly a kite.
与方程3x+8=68的解相同的是( )