把下列句子合并成一个宾语从句（每空一词）
What are they doing for vacation? Jim asks ...
Jim asks ____ ____ ____ doing for vacation.

What are they doing for vacation?为特殊疑问句，充当宾语从句时，连接词要用相应的特殊疑问词，所以第一空为what。后边要用陈述语序，将助动词are放在主语they的后边即可。变化后为Jim asks what they are doing for vacation.

略