Making suggestions and invitations

Expressions: 

Would you like to + verb?
Why don't we + verb?
What about  + -ing?
How about  + -ing?
Let's + infinitive without to.

Accepting suggestions and invitations

Sure. I'd love to.
That’s a great idea.
That sounds great.


Refusing suggestions and invitations
I don't think so.
I'm not sure about that.

Examples

Would you like to see our famous buildings? Sure. I'd love to.
Why don't you visit us? That sounds great.
What about meeting us? That's a great idea.
How inhabiting the Earth? I don't think so.
Let's meet outside the Earth. I'm not sure about that.