间接,直接引语互换的问题请看题：1：The woman told us that she did not like Am

间接,直接引语互换的问题
请看题：
1：The woman told us that she did not like American movies.
The woman said to us i don't like.
2:The teacher told the students that they were going to have a ..
The teacher said to the students“they are going to”.
3:She said that she would try to finish reading the book.
She said,“I will try to ”.
4:“Mum has gone to the store,”the son said to his father.
The son told her father that mum had gone to the store.
5:“A friend in need is frined indeed,”Mum said to me.
Mum told me that a friend.
为什么1/2 told 要改成said,为什么第3题said不改,为什么4/5 said 要改told?
PS:在什么情况下可以省略that,什么时候不能省略。