填空题。
【小题1】__________ (be) there many trees in this forest in the past?
—Yes, there __________ (be). But now there __________ (be) not many trees.
—__________ people __________ (plant) more trees in the future?
—I don't know.
【小题2】They __________ (plant) trees tomorrow.
【小题3】We __________ (visit) the farm next week.
【小题4】We're going to __________ (have) a picnic in the park.
【小题5】When are you going to __________ (play) chess?
