网络机顶盒小米:We often see some English letters on envelops. What does "p.p." mean?

We often see some English letters on envelops. What does "p.p." mean? what table do we often see in fields? we can see some plant near our school. we often ( ) there. There is a bookcase against the back wall. There is a window and we can see some lockers through it sing-,we,dance,often,and(.) what will we see when we ground We did see a movie. Mary often helps her mother do some housework. with a sign we can get some .