watch it的用法和樣例：
例句
- Watch it, there's some broken glass on the floor.
當心，地板上有一些碎玻璃。 - Be careful, he'll argue you round to his opinion before you know it.
當心，他會在你發現之前，使你轉變態度。 - Be careful or it will fall off the shelf.
小心點，否則東西會從架子上掉下來。 - You'd better watch it.If you keep being cheeky, I'll send you to the Headmaster.
你最好還是小心點，要是你老是這樣厚顏無恥，我將把你送到校長那裡去。
