lack of是形容词短语还是动词短语,怎么用?

是名词短语,不是形容词短语
例句：
1、One of the possible complicating factors,said Gill,could be lack of communication between the People's Liberation Army,which has control of the plane on Hainan,and the Foreign Ministry in Beijing.
CNN:Plane crew safe,China assures U.S.
2、Well here we are,seven months into the job,and he certainly can't be accused of lack of impact.
BBC:'Stop talking down the economy'
3、Now,point for point,the big difference between the degrees of the upgrade seem to be the lack of a new case.
ENGADGET:Apple WWDC 2009:the good,the bad,and the ugly