题目

为什么He said he must leave early等效转换是He said he would have to leave early?而不是He said he had to leave early
为什么这里have to表示将来要用将来时啊,在We have to leave early tomorrow中have to同样是表示将来,却没用will have to

提问时间：2020-10-12

答案

He said he must leave early等效转换是
He【 said 一般过去时】he 【would have to 过去将来时】 leave early
即,过去说他将要做某事.
时态搭配原则：
主句用过去时态,从句只能是过去的某种时态形式【表示客观事实和真理的情况例外】