18课：A:Is the schoolbag fat?B：Yes,he is.=He is a fat schoolbag.
20课：A:Is the brown schoolbag heavy?B:Yes,it is.A:Is thebrown schoolbag light?B:No,it isn撇t.
看听学第一册18.20课句型~十万火急（悬赏20）
18课：A:Is the schoolbag fat?B：Yes,he is.=He is a fat schoolbag.
20课：A:Is the brown schoolbag heavy?B:Yes,it is.A:Is thebrown schoolbag light?B:No,it isn撇t.