This tends to make you look unprofessional.It is OK to put one hand in a pocket but ensure there is no loose change or keys to jingle around.This will distract the listeners.

• 一只手放在口袋里是没有问题的，但要注意，你的口袋里没有能叮当作响的硬币或钥匙之类的东西，他们会分散听众的注意力；