1. Let somebody/something down

to not do something that someone trusts or expects you to do.

: The worst feeling is having let our fans down.

완료동명사 인가요~??.?

2. To Let 

written on a sign outside a building to show that it is available for renting.

outside가 전치사 맞나요~?,?

3. let fly (something) 

to suddenly start shouting angrily at someone.

: The prisoner let fly with a torrent of abuse.

let fly (something) with

to suddenly attack someone , especially with bullets or a weapon that is thrown.

:The soldiers let fly with a hail of machine-gun fire.

선생님 ㅠㅠ 동사 let의 짝은 let go of + 명사 구조처럼

전치사 with 뒤에 나온 명사인가요?

아니면 동사 let 다음에 let의 목적어가 생략된 구조인가요?ㅠㅠ