第5题: [单项选择]若外加电压随时间正弦变化，当磁路饱和时，单相变压器的励磁磁动势随时间变化的波形是（）。 A. 尖顶波 B. 平顶波 C. 正弦波 D. 矩形波 参考答案:A 答案解析:变压器的空载电流I0包含两个分量，一个是励磁分量，作用是建立磁场，产生主磁通，即无功分量；另一个是铁损耗分量，作用是供变压器铁心损耗，即有功分量。
由于空载电流的无功分量远大于有功分量，所以空载
第11题: [简答题]Questions 8--12 Answer the following questions by using NO MORE THAN three words. In which period did Chanel lose respect of the public 参考答案:World War Ⅱ 答案解析:Paragraph 6: One could say perfume helped keep Chanel’s name pretty throughout the period when her r
参考答案:
[范文]
(1)Dear Sir，
(2)I am writing to complain about the poor quality of the goods sold in your store. A month a go，I bought a cassette player in your store. But since the day I bought it，(3)it has ruined four of my favorite cassettes，which is a great loss to me. And I can not use it any more. I think it is obviously defective and the quality of it is so unsatisfying.
(4)I want you to repair it for me. If you can’t repair it well，I expect you to exchange it with a good one.
I choose to complain to you because I am sure you can solve my problem. (5)And I do hope you can deal with it as soon as possible.
I’m looking for ward to your early reply.
(6)Yours sincerely，
(7)Li Ming
这是一则投诉信。写时要注意信息丰富，要求明确。以下是书写的基本内容。
(1)称呼；
(2)表明写信目的及要投诉的事物；
(3)介绍问题所在，defective意为“有问题的，有缺陷的”；
(4)要求对方如何解决，exchange意为“交换，更换”；
(5)希望对方尽快答复，deal with意为“处理”；
(6)结束语；
(7)署名。
投诉信黄金模板： 称呼，
I am writing to complain about l.说明写信目的. A month ago，I bought 2.讲明事情经过和存在的问题. I think 3.表明自己的观点态度.
I want you to 4.说明自己的要求和期望.
I choose to complain to you because I am sure you can solve my problem. And I do hope you can deal with it 5.希望对方尽快处理.
I’m looking forward to your early reply. 结束语 署名
