lack的用法1.lack(for)sth.缺少2.belacking(in)sth.缺乏.3.(a)lackof....方面的短缺三种用法完全混在一起,例句：1.Alex'srealprombleisthathelacksconfidence.2.Heseemedtobelackingincourage3.LackofvitaminBcanpr

Question

lack的用法
1.lack(for) sth.缺少
2.be lacking (in) sth.缺乏.
3.(a) lack of....方面的短缺
三种用法完全混在一起,
例句：1.Alex's real promble is that he lacks confidence.
2.He seemed to be lacking in courage
3.Lack of vitamin B can produce a variety of symptoms
网上查的回答完全不能解释我的疑问~求正解.
---What about the student in your class,Mr.Wang?
---The doctor said that __ sleep caused him poor memory and poor concentration.
A.lacking of B.lacked in C.lacking D.lack for

Answer 1

1.lack sth. lack做动词；
2.be lacking in. lacking为形容词
3. lack of.. 整体可以做主语或宾语