You might at least phone if you know you're going to keep someone waiting.

如果你知道你会让别人等待，你至少可以打个电话。

youdao

It's not polite to keep someone waiting when you've placed the call.

如果电话是你打的，让对方久等是不礼貌的。

youdao

It's not polite to keep someone waiting when you've placed the call.

如果电话是你打的，让对方久等是不礼貌的。

youdao