用括号内所给动词的适当形式填空。
小题1:I ________ (read) a novel last night when I heard knocks at the door.
小题2:The young man ________ (live) alone since he graduated from college.
小题3:Be careful ___________ (not fall) off the ladder.
小题4:The actor and director ________(be) coming to give us a speech next weekend.
小题5:I overslept this morning. By the time I got to the train station, the train ________ (leave).