He’ll be free tomorrow.变为间接引语

He says that he'll be free tomorrow
这是一般现在时时态的间接引语变换，只需要加that就够了，用于引导从句。从句的内容也不需要变换时态。

如果是变成过去时：
He said that he would be free tomorrow.
从句的will也要变成它的过去时would，表示一种过去的将来的概念。

一般现在是的直接引语变间接引语，从句时态不变
一般过去时的直接引语变间接引语，从句时态往前推一格（一般现在时变一般过去时，一般过去时变过去完成时，现在进行时变过去进行时，一般将来时变过去将来时）
he says he will be free tomorrow.

一、将下面的直接引语变成间接引语
1 "Why were you so excited today?" Tom asked Bob.
→ Tom asked Bob why he was so excited that day.
二、将下面的直接引语使用括号中的词变成间接引语
1 "I'm doing a biology experiment now."(then)
→ He said that he was doing a biology experiment then.
2 "I'm not free today."(that day)
→ He said that he was not free that day.
3 "I must finish my paper this week."(that week)
→ He said that he must finish his paper that week.
4 "I'll have to stay in the lab until tomorrow."(the next day)
→He said that he had to stay in the lab