This is a little easier than explaining to your boss why you are 10 minutes late. You can think of an excuse ahead of time, or tell them about an appointment so you can leave early. You can use the same excuses as the ones I mentioned earlier. You just have to change the wording a little and make it future tense. 

这比向你的老板解释为什么迟到10分钟要简单得多。你可以提前想一个理由，或者告诉他们你有约了，这样你就可以提前离开。你可以用我之前提到的那些理由。你只需要稍微改变一下措辞，然后用一个将来时态。

"I have to leave a little early today. Is it ok if I finish my work at home?" 

我今天得早点下班了，我在家完成我的工作可以吗?

"I have a dentist appointment at four. I have to leave early today." 

我四点约了牙医，我今天得早点下班了。

"I have a dentist appointment tomorrow at four. Is it ok if I leave early tomorrow?" 

明天四点我约了牙医，明天我可以早点下班吗？

"I have to pick up my wife at the airport tomorrow. Is it ok if I leave at three?"

明天我要去机场接我的妻子，我三点离开可以吗？

"I have a conference with my son's teacher tomorrow at three thirty. I have to leave at three. Will that be ok?" 

明天三点半我要和我儿子的老师开个会，我必须在三点离开。可以吗？

"I have a terrible headache. Is it ok if I leave early today?" 

我头痛的厉害，今天我可以早点下班吗？

"I think I might be coming down with the flu. I should get some rest and try to fight this thing off early. May I leave early today?" 

我想我可能是得了流感，我应该休息一下，试着早点结束这事。我今天可以早点走吗?

"I'm not feeling well. I think I should get some rest. Will it be ok if I go home early today?" 

我感觉不舒服，我想我应该休息一下，我今天早点回家行吗?

"My son got sick and I have to pick him up from school. Will that be ok?" 

我儿子生病了，我必须去学校接他,可以吗？