ask for help的用法及例句

　　You can ask for help whenever you need it.

　　你如果需要帮助随时可以提出来。

　　I know that this is a bad time to ask for help.

　　我知道在这时候要求帮助不合适。

　　Why didn't you ask for help, rather than trying to do it on your own?

　　你干吗非得自己干，而不请人帮忙？