Lily often helps her sister _____ her homework. [ ]
A. for
B. at
C. of
D. with
答案:D
解释下列词语的含义。
①逆来顺受:____________________________________________
②半死不活:____________________________________________
③胆战心惊:____________________________________________
④不由自主:____________________________________________
企业持续发展的必需是什么?