29.祈使句变成间接引语时，将祈使句改换成动词不定式，然后置于引导间接引语的I/we/he/she/they told/ased him等之后。
“Be quiet!”I told him.
I told him to be quiet.
“Sit down and don’t move,”the policeman said to the young man.
The policeman told the young man to sit down and not to move.
“What a good idea it is!”
He said what a good idea it was.
He said that it was a good idea.
“How fantastic the students’ performance is!”
He said how fantastic the students’ performance was.
He said that the students’ performance was fantastic.
Modal Verbs:need,dare,used to,ought to