Use correct form to fill the blanks.

1） They went there _____________ (see) their parents last weekend. 2) Can you imagine yourself _____________ (stay) on a lonely island? 3) _____________ (collect) stamps is very interesting. 4） Who was the last one ________________ (leave) the classroom last night. 5) He worked hard,only _______________ (fail) at last. 6) No one can stand ___________________ (laugh) at. 7) The light in the office is still on.He forgot ___________ (turn) it off. 9) __________________ (not finish) her homework,the little girl may not go to bed. 10) Since he had not received her reply,he decided _________ (write) a second letter.