They are visiting their friends .they
问题描述：
They are visiting their friends .they
答
Teenagers usually feel they could survive on their own and are peer group or unable to attach to groups which is stressful for parents
答
对括号中的部分提问：
They are (visiting their friends).
他们在看望朋友
(What) (are) they doing?
他们在做什么?
显然你后面的句子中少了doing这个词