英语博客：Questions tags.

　　As you study English, you will become familiar with question tags. A tag is a little something that is added on, just like the tag on your shirt that tells you the size and type of material. We use question tags all the time in English to add a brief question to the end of a sentence. Some examples are:
It isn't raining, is it?
He works in real estate, doesn't he?
You're okay, aren't you?
You might have noticed already, that there is a pattern that is followed when using question tags. Usually, when the sentence is positive, the tag is negative. And vice¹ versa. Also, the same auxiliary² verb should be used, though there are some exceptions to this rule. Listen to the following that use the verb to be:
This dress is too tight for me, isn't it?
The film is going to start, isn't it?
They're late, aren't they?
We're on time, aren't we?
She's our tour guide, isn't she?
You can see the pattern quite easily here. In the tag, the subject comes at the very end. Before that, you simply put the verb 'to do' or 'to be' in its correct form, and contract it into a negative. So, 'we are' becomes 'aren't we', 'she is' becomes 'isn't she', 'they did' becomes 'didn't they', and 'he does' becomes 'doesn't he' etc. There are a few exceptions to the rule that I will cover at the end of the podcast.
Let's try the opposite way around, negative to positive. When I read these examples, listen closely to the verb form:
It isn't raining, is it?
We're not in a hurry, are we?
I'm not in the wrong building, am I?
He doesn't have any spare change, does he?
They don't sell hot coffee here, do they?
Can you see the pattern? Once you get used to it, it's as easy as riding a bicycle, isn't it? Let's go over some of the exceptions. When we are using the verb to be with the 'I' form, we end up using 'are' or 'aren't' as the tag, instead of 'am'. Let's listen to some examples:
I'm picking you up at 3pm, aren't I?
I'm ordering the cake tomorrow, aren't I? * Note, this second sentence is more like a confirmation³, rather than a question.
Now let's look at the 'you' form with the verb 'to have to'.
You have to study for your exam, don't you?
We have to cook the fish while it is fresh, don't we?
She had to wash the car, didn't she?              We use, as you can see, the verb 'to do' in the tag, after we use 'to have to' in the main part of the sentence. Likewise, with a negative statement using 'to have to', we would use 'to do' in the positive.
You don't have to drive tonight, do you?
They didn't have to pay again, did they?
He didn't have to go to the office for more paper, did he?
So, there you have it. Like most things, it's a question of practice. But, you are all very clever, aren't you? You didn't have much of a problem with regular questions, did you? And, I know that you will practice and learn tags very well, won't you?

1 vice   

n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的

参考例句：

• He guarded himself against vice.他避免染上坏习惯。
• They are sunk in the depth of vice.他们堕入了罪恶的深渊。

2 auxiliary   

adj.辅助的，备用的

参考例句：

• I work in an auxiliary unit.我在一家附属单位工作。
• The hospital has an auxiliary power system in case of blackout.这家医院装有备用发电系统以防灯火管制。

3 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。