n.
（常与of连用）缺乏；需要
There is no lack of vegetable.
蔬菜不缺.
The lack of rain aggravated the serious lack of food.
"由于干旱少雨,缺粮问题更加严重."
vt.是及物动词,直接接所缺乏的东西就可以：
缺乏；不足；没有
He lacks courage.
他缺乏勇气.
Their actions lack consistency; they say one thing and do another.
"他们言行不一,说的是一回事,做的又是另一回事."
These photographs lack definition. You'd better have them taken again.
"这些照片不够清晰,你最好得重拍."
如果lack作动词时后面加in则必须是be lacking in这种形式：
Is she lacking in courage?
她缺乏勇气吗?
如果lack作动词时后面加for则通常用于否定句：
He lacks for nothing.