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问题 填空题

从C、H、O、S、Cu五种元素中，选择适当的元素组成符合下列要求的一中物质，将其化学式填入空格中．

（1）具有可燃性，可做火箭燃料的单质______；（2）最简单的有机物______；

（3）导致人煤气中毒的气体______；（4）用于配制波尔多液的盐______．

答案

（1）具有可燃性，可做火箭燃料的单质是氢气，其化学式为：H2

（2）最简单的有机物是甲烷，其化学式为：CH4

（3）导致人煤气中毒的气体是一氧化碳，其化学式为：CO

（4）用于配制波尔多液的盐是硫酸铜或五水合硫酸铜，其化学式为：CuSO4或CuSO4?5H2O

故答案为：（1）H2 （2）CH4 （3）CO     （4）CuSO4或CuSO4?5H2O

阅读理解
阅读理解。
                                                       BORDER 
                                                    CROSSINGS
     While there are no restrictions on the amount of money that you can bring across
the border. You must report to both the US and Canadian border services amounts equal
to or greater than $10.000. 
                        PERSONAL EXEMPTIONS (免税) ON PURCHASES 
                                  AMERICANS RETURNING TO THE US
     Less than 48 hours: $ 200 US
     48 hours or more: $ 800 US duty-free personal exemption. 
                                next $ 1.000 US at 3%
                                Including up to 100 cigars and 100 cigarettes. 
                                CANADIANS RETURNING TO CANADA
     Less than 24 hours: $ 50 CAN
     48 hours or more: $ 400 CAN 
                                Including up to 100 cigars and 200 cigarettes.
     7 days or more: $ 750 CAN
                             Including up to 100 cigars and 200 cigarettes.
                                    DOCUMENTATION NEEDED FOR
                                            BORDER CROSSING
                          LAND OR SEA TO THE US(INCLUDING FERRIES)
     A valid passport or passport card, or a NEXUS card.
     (A NEXUS card is a Trusted Traveler Program that provides quick travel
for pre-approved, low risk travelers through special lanes.)
     A recent Washington State, New York or BC driver's license.
     Note: Children 15 years of age and younger require only a birth certificate or
     copy. (Certified copies are not required but are advised.)
                                         AIR TRAVEL TO THE US
     A valid passport, an Air NEXUS card, or a U.S. Coast Guard Merchant
     Marine Document.
1. If a Canadian who is on a 7-day trip to New York buys $ 800 CAN worth of goods, how much should he
pay tax on when returning home?
[ ]
A. $ 800 CAN
B. $750 CAN
C. $ 400 CAN
D. $ 50 CAN
2. For an American citizen on a 2-day tour of Canada, how much tax does he have to pay on $ 1.600 US
worth of purchases when returning to the US?
[ ]
A. $ 24 US
B. $ 48 US
C. $52 US
D. $ 200 US
3. What documentation should a couple with a 7-year-old child carry when they drive a car from Canada to
America?
[ ]
A. A BC driver's license, an Air NEXUS card, and a birth certificate.
B. An Air NEXUS card, a U.S. Coast Guard Merchant Marine Document, and a birth certificate.
C. Two valid passport cards and a certified copy of a birth certificate.
D. A NEXUS card, a U.S. Coast Guard Merchant Marine Document, and a certified copy of a birth certificate.
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单项选择题

线迹形成的过程一般包括钩线、挑线、送布（）等环节。

A.引线

B.钩线

C.挑线

D.送布
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