A．He doesn’t live in the dormitory any more.
B．He came back to school this semester.
C．He’s busy moving into a new room.
D．He can’t talk about it right now.

A．Because nothing in the world can be taken for granted.
B．Because one always needs hard lessons before he becomes ma- ture.
C．Because each young generation is curious about everything.
D．Because the young generation must learn lessons to know drugs.