I haven't heard from Henry for a long time.-What do you supp

没有,suppose to do,是be supposed to do 应该做什么事
这里其实是：I suppose what has happened to him,是宾语从句,意思是：我猜 他发生了什么事,特殊疑问句,将特殊疑问词提前到句首变成了题目 What do you suppose has happened to him