Idiom: (to) drop by

Definition:

to pay a short, often unannounced visit

Examples:

1) If we have time before the movie, let’s drop by my house.

2) “Hi, I was in the neighborhood and I thought I’d drop by”.

中文解釋：http://www.youzienglish.com/main/idiom_of_the_day/to_drop_by/cn/