我看着他给我的东西，快速做了个减法。I looked at what he'd given me and did a quick subtraction.用减法得出差额.The difference is found by subtraction.加号用于加法;减号用于减法.The plus sign is used in addition and the minus is used in subtraction....
任何有较强重力的物体都会对其他物体产生引力。Anything with strong gravity attracts other things to it.重返大气层的航天器受到重力的作用。Spacecraft which are re-entering the earth's atmosphere are affected by g forces.由于重力的关系,苹果往下掉.An apple falls down beca...
All spacemen must be able to bear acceleration.所有太空人都应能承受加速度.She said with a straight face she saw green spacemen in the back yard.她面无表情地说她在后院看到绿色外星人.There are five spacemen in the spaceship.宇宙飞船里有五个飞行员....