It seems that the old man for something over there.
pay attention, think about, close down, hang on, fall off
深：①颜色浓；②距离开始的时间很久；③深奥；④从表面到底的距离大。
A河水很深。____
B这件衣服颜色太深了。____
C夜深了，爸爸还在加班。____
D这道题太深了，小兰不会做。____
下列物质中含有氧气的是（ ）
