it's a sunny dan.Let us go out.这里为什么用US,如果用Let's go out可以吗?

it's a sunny dan.Let us go out.这里为什么用US,如果用Let's go out可以吗? it's sunny let's go out for a w___ LET'S GO OUT Let's go out. Let's go to the movie,shall we?与Let us go out for a walk,wil 急,Let's go to the movie,shall we?与Let us go out for a walk,w "Let's go out for a picnic,''wang lin said to us.改为间接引语 let go /let's go/ let us go let's go out for a walk? -----------!let's go out for a walk let's go out to Let us go out and fly kites.It is f____