how to use gestures
make sure all your gestures are smooth and natural； 所有的动作都应该流畅自然；
don't put your hands in your pockets； 不要把手插在口袋里；
let your hands and arms drop naturally to your side ，gently fold both indes fingers together，without wringing or gripping your hands in any way；
将手和手臂自然地在身体两侧下垂，轻微屈起食指，不要扭在一起或紧握拳头；
let your hands do what they want to do as long as they don't go back into your pockets or make obscene gestures.
手想要怎样就让它怎样，直到它不再回到你的口袋或在听众面前做一些惹人讨厌的手势。
point at imaginary objects and don't point at others with your index finger；
手可以指点着假想的物体，不要用食指指着别人；
size or quantity can also easily be shown by expanding or contracting the hands；
心寸的大小和数量的多少也可以通过两手的扩张和收缩来演示；
gracefully show your audience the appropriate number of fingers by holding your hands at a 45 degree angle from your head；
手抬起并与头成四十五度角，优雅地用手势表示出数字；
to emphasize physical size such as length，width，hold your hands out in front you widely apart to move them up and down.
如果想要强调长度尺寸的大小，将两手伸向前方，尽量分开，并上下移动。