When to use -(으)ㅂ시다

1) When you address a large group of people

Ex)자원을 절약합시다.= Let's save resources.

Ex)환경을 보호합시다.= Let's protect the environment.

Ex)책을 읽읍시다.= Let's read books.

2) When you don't want to be polite

Ex)조용히 좀 합시다.= Let's be quiet.

3) "Please, let me do something!"

Ex)잠 좀 잡시다.= Let me sleep.

Ex)지나갑시다.= Let me pass through.

Ex)내립시다.= Let me get out.

4) Polite and formal in written language