on the latch

(of a door or gate) closed but not locked

（门）关着但没锁上

let yourself in, the door's on the latch.

你进来吧，门没锁。

latch on

(of a breastfeeding baby) manage to get its mouth into the correct position around the nipple

（哺乳婴儿）用嘴叼到乳头

latch on to informal 非正式

attach oneself to (someone) as a constant and usually unwelcome companion

纠缠

he spent the whole evening trying to latch on to my friends.

他整个晚上都纠缠着我的朋友。

understand the meaning of (something)

理解，明白

[with clause]she'll soon latch on to what is happening.

她很快就会理解发生了什么。

latch on to 或 latch onto

To get hold of; obtain

取得；得到

latched on to a fortune in the fur trade.

在皮毛生意中赚了一大笔钱