be thick as thieves (be thik az thivz)

Idiom Friendship

含义

to be very close friends

成为非常亲密的朋友 (chengwei feichang qinmi de pengyou)

例句

"Those two have been thick as thieves since childhood."

"这两个人从小就是非常亲密的朋友。" (Zhe liang ge ren cong xiao jiu shi feichang qinmi de pengyou.)