They _________ solve these problems in one day.　　A.can’t be able to B.will not able to C.are急111

They _________ solve these problems in one day.　　A.can’t be able to B.will not able to C.are急111
They _________ solve these problems in one day.　　A.can’t be able to B.will not able to C.are
急111

They _________ solve these problems in one day.　　A.can’t be able to B.will not able to C.are急111
选B
A选项 can't就相当于be able to,重复,排除
C选项如果是are,那么后面动词solve就不能是原形,应该是solving,所以排除C

B

你提供的答案不全！应该是：
They are not able to solve these problems in one day.

应该选B，但是你给的答案不完整。be able to相当于can，所以没有A这种用法。而对与C选项，are和solve都是动词，一个单句子中是不能同时出现两个动词的。就算用are solving也不可以，因为in one day一般和将来时连用。