My hostess latched onto me at the door , saying that I must stay one more day .

女主人在门口抓住我不放，要我再呆一天。

And latched onto you like a leech .

你喜欢并锁存到水蛭。

She latched the door carefully .

她小心地闩上了门。

It was a difficult concept to grasp , but sam latched on very quickly .

那是个难掌握的概念，但萨姆很快就理解了。

I haven 't really latched on to what you mean could you explain it again ?

我没有真正明白你的意思--能不能再解释一下？