情态动词也会变化，往回一个时态：
Will 变成 would
He said, ‘Jane will be late.’ 他说：“简会迟到。”
He said Jane would be late. 他说简会迟到。

“I will see him later.”  “我稍后会见到他。”
She said she would see him later. 她说她稍后会见到他。

Can 变成 could
“I can swim.” “我会游泳。”
She said she could swim. 她说她会游泳。

May 变成 might
“It may become colder over night.”
“夜里可能会变得更冷。”
She said it might become colder over night.
她说夜里可能会变得更冷。

如果直接引语用的是 would（将，会，要），could（能，可以，也许），might（可能，可以，也许）和 should（应该，将，会），变间接引语没有变化。

“You should speak more.”
“你应该多说话。”
She said I should speak more.
她说我应该多说话。
She said you should speak more.
她说你应该多说话。