Criticism and self-criticism necessary it helps us to correct mistakes.
A. is, in that
B. are, in that
C. is, in which
D. are, at that
网友回答
(答案→)A. is, in that
B. are, in that
C. is, in which
D. are, at that
解析：第一空是主谓一致，Criticism and self-criticism看成整体，谓语动词应用单数，第二空考查连词，in that 因为，句意：批评与自我批评是必要的因为它帮助我们纠正错误。所以选A。