下列四个城市与其所在国家、地理位置连线正确的是（ ）
A：河内——越南——红河沿岸
B：曼谷——泰国——伊洛瓦底江沿岸
C：万象——老挝——湄南河沿岸
D：金边——缅甸——湄公河沿岸
把肯定句改为否定句。
Model: It looks good.
It doesn't look good.
We are all here Mary. She is at home.
