根據(jù)中文意思和英文提示詞語，寫出四句語法正確、意思連貫的話。

上周六王明跟同學(xué)們到郊外玩，中午他和同學(xué)們一起在樹下吃飯，飯后他們……

1. last Saturday, Wang Ming, go outing, with his classmates

2. they, have lunch together, under a tree

3. after lunch, there be, some rubbish around them

4. they, not go, until, they, clean up the rubbish