风湿病是（） A.乙型溶血性链球菌直接感染 B.乙型溶血性链球菌感染有关 C.流感病

函数f（x）=2^|x|的最小值为______；图象的对称轴方程为______．

质检部门将对12个厂家生产的婴幼儿奶粉进行质量抽检，若被抽检厂家的奶粉经检验合格，则该厂家的奶粉即可投放市场；若检验不合格，则该厂家的奶粉将不能投放市场且作废品处理．假定这12个厂家中只有2个厂家的奶粉存在质量问题（即检验不能合格），但不知道是哪两个厂家的奶粉．

（I）从中任意选取3个厂家的奶粉进行检验，求至少有2个厂家的奶粉检验合格的概率；

（Ⅱ）每次从中任意抽取一个厂家的奶粉进行检验（抽检不重复），记首次抽检到合格奶粉时已经检验出奶粉存在质量问题的厂家个数为随即变量ξ，求ξ的分布列及数学期望．

A long time ago, before human beings lived on the earth, little coral polyps（水螅）settled around tropical （热带的）coastlines and constructed corals. Over a long period they created lots of reefs. Yet, pollution, climate change and commercial fisheries are limiting the chance of future generations knowing or seeing many of the reefs and sea creatures that exist. Hence, take action to dive now and you can explore the underwater world.

Commercial underwater diving began in ancient Greece. Diving in general means that the whole body is completely in water. On that account there are lots of exciting and quite adventurous ways to dive, like shark cage diving, scuba diving（戴水肺潜水）and reef diving.

There are great coral reefs all over the world, but usually they are situated in warm, clear water such as the Pacific and the Indian Ocean, where they grow best. This is why there are no coral reefs on the west coast of South Africa. However, South Africa’s east coast offers much brightly coloured sea life.

In South Africa more than 100,000 dives a year are made just in coral reefs, which are one of the natural wonders of the world. To see the whole beauty of the reef the right diving gear（设备） is an essential requirement. This means a perfect fitting diving mask and fins, as well as a snorkel（呼吸管）and a friend. Diving alone is dangerous because there may be strong currents you are not aware of, and it’s a lot more fun to share the experience with someone. However, before you can explore the deeper sea, a certificated and checked scuba, a wetsuit and of course a license will be needed. Whether you choose the snorkel or the scuba to spot the colourful underwater world, try to touch as little as possible, be careful with the corals and don’t strike the fishes, because the complex ecosystem is very sensitive.

小题1:The following factors probably affect coral reefs EXCEPT ________.

A．sea creatures

B．pollution

C．fishing

D．climate change小题2:Which of the following is true according to the passage?

A．Human beings appeared before corals were created.

B．One needs a license to dive into the deeper sea.

C．Diving alone has many advantages.

D．The origin of diving is in modern Greece.小题3:There are no coral reefs on the west coast of South Africa probably because of a lack of ________.

A．large waters and soft sand

B．warm currents and delicious food

C．friendly creatures and flat seabed

D．clear water and suitable temperature小题4:The last paragraph mainly tells us ________.

A．diving alone under the sea is rather dangerous

B．some matters we need pay attention to when diving

C．South Africa is a popular place for diving

D．what we should wear when diving

电子秤一般在出厂前（）。

A、不作调试

B、调试合格

C、已经检定

D、未做检定

脂肪酸β-氧化第一次脱氢的辅酶是（）

A.NADP⁺

B.HSCoA

C.FMN

D.NAD⁺

E.FAD