[\ I__attend the conference next monday.A must .B am able to .C will have to 为什么A不行

[\ I__attend the conference next monday.A must .B am able to .C will have to 为什么A不行
[\ I__attend the conference next monday.
A must .B am able to .C will have to 为什么A不行

[\ I__attend the conference next monday.A must .B am able to .C will have to 为什么A不行
我觉得A才是正确答案,C不可能对啊.
have to本身就可以理解为情态动词的行列,必须……不得不……,哪有在情态动词面前再加will 本身就表示一种情态,不存在现在将来的问题.
这个在语法上是绝对有错误的.
A完全没问题.
如果要用B的话,will be able to可能更恰当一点.