1.I am sorry I __have kept___ (keep) you waiting for such a long time.
2.I saw him _reading___ in the room at that moment.(read)
3.He made an apolopy for _being late___ (be)
4.The boy is happy because he __has sold___ (sell) out all the newspapers.
5.Where _have____ you _been___ (be) these days?
6.Light _travels___(travel) much faster than soud.
7.He said the lights in the room __had gone__ (go) out when he opened the door.
8.You should better _stay____(stay) at home.
9.You had better __not put___(not put) the picture up on the wall.
10.I saw the traffic accident __happen___ (happen) yesterday.