1 What does the young man do (这个年轻人是干什么的）
He is a business.
2 What did he do when he saw a man come into the office
(当他看到有个人进来时在干什么）
Wishing to appear busy,the businessman picked up the phone and pretended that he had a big deal working.
3 What will the visitor do (刚才来那个人准备干什么）
He will install the phone.