变复数1.This is a knife2.That is an apple tree3.He is a policem
变复数 1.This is a knife 2.That is an apple tree 3.He is a policeman 4.The ruler is mine 5.What is his name? 6.There is a sheep on the hice? 7.Who is that man?
thoes are knives. those are apple trees. they are policemen. the rulers are mine. what are their names、 there are sheep on the hice. who are those men?