爱思英语编者按：下面有2封英文书信，你能分辨哪封是正式信件，哪封是非正式的吗？

信件1：

Dear Sir or Madam,

I am writing with regard to a flight that I missed due to a mistake by one of your employees.

Two weeks ago I was due to catch a flight to Rome, where I intended to spend four days on holiday. Unfortunately, the attendant at the check-in desk gave me a boarding card for a different flight, and I did not notice the mistake until I arrived at the departure gate and it was too late.

As a result of the error, I was not allowed to board the flight to Rome, and this caused me great inconvenience. I had to book a new flight two days later, which meant that I missed two days of my holiday and I spent an extra £200.

As the mistake was caused by your company, I hope that you will compensate me for the cost of the additional flight, as well as for my taxi fares to and from the airport.

I look forward to receiving your response.

Yours faithfully,

Paul Jones

信件2：

Dear John,

I’m just writing to let you know that I’ve moved house.

As you know, I went for an interview for a job here in London. Well, they gave me the position! It would have been impractical to travel down from Manchester every day, so we’ve found a house here, in a nice part of London called Greenwich.

Our new house isn't ideal. London prices are crazy, and we were only able to afford a one-bedroom flat. But on the bright side, it’s on the ground floor, it’s got nice big windows, and a lovely view out onto the garden.

If you ever fancy a trip to London, you’re more than welcome to come and stay. It would be great to see you. From where we live, it’s only a quick ride on the underground into the city centre, so we could do some sight-seeing together.

Keep in touch!

All the best

Mike

答案是第一封正式，第二封非正式。理由如下：

Formal letter
正式信件

Beginning: Dear Sir or Madam
用Dear Sir or Madam开头

Stating the purpose: I am writing with regard to
用“I am writing with regard to”说明目的

Formal choice of language: due to, I intended, as a result of, caused me great inconvenience, compensate me, the additional flight
使用以下正式词汇：due to, I intended, as a result of, caused me great inconvenience, compensate me, the additional flight

No contractions: I am (not "I'm")
不使用缩写：写成I am而不是I'm

Ending: I look forward to receiving your response. Yours faithfully,
结尾： I look forward to receiving your response. Yours faithfully,

Informal letter
非正式信件

Beginning: Dear John
用Dear John开头

Stating the purpose: I'm just writing to let you know that
用“ I'm just writing to let you know that”说明目的

Informal choice of language: As you know, Well, prices are crazy, on the bright side, it's got nice big windows, a lovely view, if you ever fancy, great to see you
使用以下非正式词汇：As you know, Well, prices are crazy, on the bright side, it's got nice big windows, a lovely view, if you ever fancy, great to see you

Use of contractions: I'm, we've, isn't, it's
使用缩写：I'm, we've, isn't, it's

Ending: Keep in touch! All the best
结尾：Keep in touch! All the best