lack n.可数,缺乏 lack of sth （物质上的,具体的） a lack of sth
a lack of money 缺乏资金
There was no lack of wolunteers.志愿者不乏其人.
lack vt.缺乏,不足,短缺 lack sth
He lacks confidence.他缺乏信心.
lacking adj 缺乏的 be lacking in （某一方面,抽象的）
She's not usually lacking in confidence.她平时并不缺乏信心.