Which thing is the most important

He asked （which thing was）the most important.

分析：主句是一般过去时,从句要改为相应的过去时,即is ->was

同义转换可以转换的东西有三部分

1 转换同义词,比如most important 可以换成 extremely crucial, points 变成views, statements等

2 变换句型,比如上句可变为被动句: The most important points of the speech should be write down

3 变换同根词词性,比如 important可以转变为其名词形式 of importance

句子可变为write down the points of the most importance of the speech