思考与探究 I.单项选择。 C )1.-It's dangerous to swim in this river. -Yes.The government has warned people. in it. A.of not swimming B.not swimming C.not to swim D.not to swimming 导航页导航页 思考与探究 Ⅰ. 单项选择。 ( )1. —It’s dangerous to swim in this river. —Yes. The government has warned people in it. A. of not swimming B. not swimming C. not to swim D. not to swimming C