let sth in
make (a garment, etc) narrower 将(衣物等)改窄, 改瘦
This skirt needs letting in at the waist. 这裙子的腰部需要改瘦. let sb/oneself in for sth (infml 口) cause sb/oneself to suffer (sth unpleasant) 使某人[自已]惹上(不愉快的事)
You´re letting yourself in for trouble by buying that rusty old car. 你买那辆生了 的旧汽车是自找麻烦. let sb in on/into sth (infml 口) allow sb to share (a secret, etc) 让某人知道(秘密等)
Are you going to let them in on the plans? 你是否打算让他们知道这些计划?