I don't know _____ by myself _____ I am alone at home .          [ ]

A. how to do , when      

B. what to do , when           

C. how to do things ,but    

D. what to do things , because

（）是家庭和谐不可或缺的重要内涵，也是夫妻家庭生活中应共同遵守的基本道德规范。

A.夫妻和睦

B.男女平等

C.邻里团结

D.勤俭持家