[词组]几个词组翻译。

in rare cases:

ad. 偶然(偶尔几次)
I meet him in rare cases.
in aid of:

a. 为了帮助(以助-)
I buy a computer in aid of studying.

NO.1---in rara cases 偶然
NO.2---aid of 帮助

第二个是帮助的意思。例句：I managed to go up the mountain with the aid of a guide.意思是再向导的帮助下，我爬到了山顶。