Formula	Verb Form
Why don't you / we go to a movie?	Use the base form of the verb in a question
We / You could go to a movie.	Use the base form of the verb in a statement
Let's go to a movie.	Use the base form of the verb with 'let's'
What about going to a movie?	Use the '-ing' form of the verb in a question
How about going to a movie?	Use the '-ing' form of the verb in a question
I suggest you / we go to a movie.	Use suggest object verb in the base form in a statement.

Let's  simple verb  Let's not  simple verb  Let's play baseball.  Let's not play football.	Why don't [I/we/you/they]  simple verb   ? Why doesn't [he/she/it]   simple verb   ? Why don't you ask her? Why doesn't she tell you?
Let's  is a polite suggestion. It does not need a subject. It is not a question. It uses a simple verb.	Why don't/doesn't...? is a question. It is used to make a polite suggestion. Don't forget the question mark at the end!

Speaking Situations: Making Suggestions

Phrases for these situations

I think you should. . .
I don't think you should. . .
Maybe you should. . .
Why don't you. . .
Why don't we. . .
Let's. . .

That's a good idea.
Thanks for the advice.
Good suggestion.
Sounds like a good idea.

Making suggestions

You heard Diana and Billy making a number of suggestions during their discussion. Here are some of the expressions they used with additional examples.

Why don't …?

Why don't we go through it now?

Why don't you call Reloc to check?

Let's ...

Let's give it a more interesting title.

Shall ...?

Shall we say three hours?

What/How about + -ing?

What about offering a buffet?

How about calling it `Ideas for Our Future'?

What/How about + noun?

What about a buffet?

What about `Ideas for Our Future'?

Modal verbs for making suggestions

`Should' (= advisable)

We should finalise the agenda and get it circulated today.

`Had better' (= advisable)

We'd better provide transport for them.

You'd better start now.

`Could' (= possible)

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