单词：CLS
[计] DOS内部命令:清除屏幕并将光标移至屏幕的左上角
n a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water)
n a metric unit of volume equal to one hundredth of a liter
n a metric unit of volume equal to one hundredth of a liter