— swim in the river? — oh no. Our teacher told us here. It’s dangerous. A. Why don’t; no

问题补充：

— swim in the river?

— oh, no. Our teacher told us here. It’s dangerous.

A. Why don’t; not swim

B. Why not; not to swim

C. Why not; don’t swim

D. Why don’t; don’t swim

答案：

A. Why don’t; not swim

(答案→)B. Why not; not to swim

C. Why not; don’t swim

D. Why don’t; don’t swim

解析：为什么不在河里游泳，why not do sth后面加动词原形，表示建议通常与hou about doing sth what about doing sth why don you do sth进行同一句转换肯定的表达是tell sb to do sth 告诉某人去做某事，否定的表达是tell sb not to do sth告诉某人不去做某事。故选B，根据下句老师告诉我们不要在那游泳。