There are some problem we need _____.A.solve B.solvingC.to solve哪个是正确答案啊?
need什么情况下作情态动词?什么情况下作行为动词?
可是参考答案是solve啊．头痛．有没有更肯定的回答啊？其实我也认为是to solve的．可是．．．