1、They must begin the woke now.
Must they begin the work now?(情态动词提到句首)
They mustn't begin the work now.(情态动词的否定句在后直接加not)
2、I need an English Chinese dictionary.
I don't need an English Chinese dictionary.(此处need是实义动词,所以是一般现在时态的基本句型)
Do I need an English Chinese dictionary?（理由同上）
3、We have got a lot of money.
Have you got a lot of money?(是现在完成时态的句型结构)
We haven't got a lot of money.但通常说成We haven't got much money.因为much常用于否定句.