激活补体经典途径的免疫复合物是()A．IgG B．IgM C．IgD D．IgA E

下列离子方程式中，正确的是 

A．氯化铁溶液中加入铜粉：Fe³⁺＋Cu ="=" Fe²⁺＋Cu²⁺

B．将含等物质的量的NaHCO₃和Ba(OH)₂溶液混合：HCO₃^-＋Ba²⁺＋OH^-="=" BaCO₃↓＋H₂O

C．少量SO₂通入次氯酸钙溶液中：Ca²⁺＋2ClO^- ＋SO₂＋H₂O ="=" CaSO₃↓＋2HClO

D．少量AlCl₃溶液滴入过量氨水中：Al³⁺＋4NH₃•H₂O="=" AlO₂^- ＋4NH₄⁺ +2 H₂O

解题说明

本大题要求判断所给出的条件能否充分支持题干中陈述的结论。阅读条件(1)和条件(2)后选择：

(A)条件(1)充分，但条件(2)不充分

(B)条件(2)充分，但条件(1)不充分

(C)条件(1)和条件(2)单独都不充分，但条件(1)和条件(2)联合起来充分

(D)条件(1)充分，条件(2)也充分

(E)条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分

方程(a²+c²)x²-2c(a+b)x+b²+c²=O有实根。
(1)a，b，c成等差数列 (2)a，b，c成等比数列

根据增值税法律制度的规定，下列各项中，属于增值税征收范围的有 ( )。

A．商场销售金银饰品

B．银行销售金银

C．邮局销售集邮商品

D．邮票厂印制邮票

阅读理解

     Every culture has a recognized point when a child becomes an adult, when rules must be followed

and tests passed.

     In China, although teenagers can get their ID cards at 16, many only see themselves as an adult

when they are 18. In the US, where everyone drives, the main step to the freedom of adult life is

learning to drive. At 16, American teens take their driving test. When they have their license, they drive

into the grownup world.

     "Nobody wants to ride the cheese bus to school, " said Eleanor Fulham, 17. She brought the

pressure back to memory, especially for kids from wealthier families. "It's like you're not cool if you

don't have a car, " she said.

     According to recent research, 41% of 16 to 19yearolds in the US own cars, up from 23% in 1985.

Although, most of these cars are bought by parents, some teens get parttime jobs to help pay.

     Not all families can afford cars for their children. In cities with subways and limited parking, some

teenagers don't want them. But in rich suburban areas without subways, and where bicycles are more

for fun than transportation, it is strange for a teenager not to have a car.

     But police say 16yearolds have almost three times more accidents than 18 to 19yearolds. This has

made many parents pause before letting their kids drive.

     Julie Sussman, of Virginia, decided that her son Chad, 15, will wait until he is 17 to apply for his

learner's permit.

     Chad said he has accepted his parents' decision, although it has caused some teasing from his friends.  "They say that I am unlucky, " he said, "But I'd rather be alive than driving, and I_don't_really_trust_my

_friends_on_the_road,_either."

     In China as more families get cars, more 18yearolds learn to drive. Will this become a big step to

becoming an adult?

1. Which may serve as the best title of the article?

A. Cars Helping You to GrowUp

B. Driving into the GrownUp World

C. Teenagers' Driving in America

D. Recognized Point of Becoming an Adult

2. 16yearold drivers have more accidents possibly because________.

A. they want to show themselves off

B. they are never experienced drivers

C. older people always drive better

D. they never drive carefully on the road

3. Which may NOT be taken into consideration when deciding whether to buy a car?

A. How well off the family is.

B. Whether the kid is old enough.

C. What traffic condition there is around.

D. Whether it's practically needed.

4. When Chad said "I don't really trust my friends…he meant that________.

A. he might run into his friends if he drove

B. he didn't agree with his friends

C. he might not be safe if his friends drove

D. he was afraid that his friends might well lie to him

5. The passage mainly gives information about ________.

A. an American culture

B. a cultural difference between America and China

C. a change in the Chinese culture

D. the relationship between driving and a person's development

杆发生弯曲变形后，轴线和外力（）的弯曲称为平面弯曲。

A.不平行

B.在同一平面内

C.相垂直

D.方向交错