mustn’t, can’t, needn’t; must, can, needThis ______be the only w

mustn’t, can’t, needn’t; must, can, need
This ______be the only way to solve the problem.?There ______be other ways of solving it.
【正确答案】：can’t / must
【题目解析】：Must表示推测意义时，意为“准是、一定是”，通常只用于肯定句；否定句或疑问句中，则用?can?代替。