加热炉对流管露点腐蚀是由于燃料含()元素在燃烧后遇水形成酸。
A、氢
B、氧
C、炭
D、硫
参考答案:A
A donation thank-you letter not only shows your good manners, 小题1: can help deepen your ties. Also, the other person will feel that 小题2: appreciate his or her contribution, however small it is.
When you are writing 小题3: donation thank-you letter, you should use the name of the donor instead of just using a basic greeting. You should thank the person sincerely for his or her support and explain 小题4: useful it proved to you. You need to tell the person the good things 小题5: their donation helped you achieve. You need to be specific as to when, how and on whom or for what the donation was used. The tone of the letter should be personal, as if you 小题6: speaking face to face to the donor.
You should send the letter in 48 hours 小题7: receiving the donation. If you fail to do that, then it should be sent over within a week. The sooner you send it, the 小题8: .
朝鲜目前被分割为南北两部分并非自然条件所致,究其分裂的根源在于()
A.南北两种社会制度的对立
B.日本曾对朝鲜实行“分而治之”政策
C.南北经济发展水平差距拉大
D.日本投降后,美苏对半岛的占领