Let's go to the playground.改为否定句如何改?为什么?

1.Let's go to the playground.改为否定句：Let us not go to the playground.（我们不要去操场,Let's是let和us的缩写）.
2.如果是Let him go to the playground改为否定句如何改?
Let him go to the playground改为否定句：Let him not go to the playground.让他不要去操场.
Let sb do sth.（让某人做某事）否定句：Let sb not do sth.（let为及物动词vt,后加动词原形.）