建设中国特色社会主义，我们必须清醒认识到的三个没有变是指什么？

（2011广西梧州，15，3分）一元二次方程x²+5x+6=0的根是________．

底阀是一种专用的（）。

A、换向阀

B、溢流阀

C、旋塞阀

D、止回阀

根据销售合同和已知资料指出一般原产地和保险单中错误的地方。
(1) 销售合同

SALES CONTRACT

Contract No.: NJTO90218
Date: FEB. 18, 2009
Signed at: Nanjing, China
The Seller: NANJING JINLING TEXTILE CO., LTD.
Address: UNIT A 18/F, JINLING TOWER, NO. 118JINLING ROAD, NANJING, CHINA
The Buyer: DEXICA SUPERMART S. A.
Address: BOULEVARD PACHECO 44, B-1000 BRUSSELS, BELGIUM
This Sales Contract is made by and between the Sellers and the Buyers, whereby the sellers agree to sell and buyers agree to buy the under-mentioned goods according to the terms and conditionsstipulated below:

Commodity and specifications	Quantity	Unit Price	Amount
GIRLS GARMENTS	10800PCS	CIF BRUSSELSEURS. 00/PC	EUR54000.00

10% more or less in quantity and amount are acceptable
Packing: IN CARTON Shipping Mark: N/M
Time of Shipment: Within 30 days after receipt of L/C
From NINGBO PORT CHINA to BRUSSELS, BELGIUM
Transshipment and Partial Shipment: Allowed
Insurance: to be effected by the Seller for 110% of full invoice value covering all risks up to port of destination and war risks included with claim payable at destination.
Terms of Payment: By 100% Irrevocable Letter of Credit in favor of the Sellers to be available by sight draft to be opened and to reach China before APRIL 1,2009 and to remain valid for negotiationin China until the 21days after the foresaid Time of Shipment. IJC must mention this contractnumber L/C advised by BANK OF CHINA JIANGSU BRANCH. ALL banking Charges outside Chinaare for account of the Buyer.
The Seller The Buyer
NANJING JINLING TEXTILE CO., LTD. DEXICA SUPERMART S.A.
钟山ALICE
(2)已知资料
装运信息：指定APL承运，装期2009.04.19；船名PRINCESS：航次V.018
装箱资料：合计108箱，装入1×20^#集装箱。
商业发票号：NJTO90218-09，签发日期2009年4月10日。
信用证号：CMKK9180205
(3)一般原产地证

缮制错误的地方有：

检查喉狭窄患者见其气道阻塞腔径的70％～90％，按Cotton分类法应诊断为（）

A.Ⅰ度喉狭窄

B.Ⅱ度喉狭窄

C.Ⅲ度喉狭窄

D.Ⅳ度喉狭窄

E.以上都不对

第15届“世界杰出女科学家成就奖”2013年欧洲地区获奖者是英国约克大学普拉蒂巴·L·盖伊，英国科技曾领先于世界。下列各项中，哪一项不是英国人的发明