早知文理百科

lack (of sth)缺少（某物）； a lack of money 缺乏资金； lack sth缺少某物 Research has been constrained by a lack of funds. 研究工作因经费不足而受限...

lack sth； lack of sth （物质上的,具体的）； be lacking in （某一方面,抽象的） Research has been constrained by a lack of funds. 研究工作因经费不...