发酵液乳化现象是如何产生的？对分离纯化产生何影响？影响乳浊液稳定的因素主要有哪些？如

已知二次函数f（x）=x²+2（a-1）x+3；

①当a=-1，且x∈[1，4]时，求函数y=f（x）的最大值与最小值；

②若函数y=f（x）在[3，+∞）上是增函数，求a的取值范围．

为什么说环境不能决定人的发展

Although there are many skillful Braille readers, thousands of other blind people find it difficult to learn that system. They are thereby shut (1) from the world of books and newspapers, having to (2) on friends to read aloud to them.

A young scientist named Raymond Kurzweil has now designed a computer which is a major (3) in providing aid to the (4) .His machine, Cyclops, has a camera that (5) any page, interprets the print into sounds, and then delivers them orally in a robot-like (6) through a speaker. By pressing the appropriate buttons (7) Cyclops’s keyboard, a blind person can "read" any (8) document in the English language.

This remarkable invention represents a tremendous (9) forward in the education of the handicapped. At present, Cyclops costs $ 50,000. (10) , Mr. Kurzweil and his associates are preparing a smaller (11) improved version that will sell (12) less than half that price. Within a few years, Kurzweil (13) the price range will be low enough for every school and library to (14) one. Michael Hingson, Director of the National Federation for the Blind, hopes that (15) will be able to buy home (16) of Cyclops for the price of a good television set.

Mr. Hingson’s organization purchased five machines and is now testing them in Maryland, Colorado, Iowa, California, and New York. Blind people have been (17) in those tests, making lots of (18) suggestions to the engineers who helped to produce Cyclops.

"This is the first time that blind people have ever done individual studies (19) a product was put on the market," Hingson said. "Most manufacturers believed that having the blind help the blind was like telling disabled people to teach other disabled people. In that (20) , the manufacturers have been the blind ones.

20（）

A.occasion

B.moment

C.sense

D.event

2006年6月20日，“扬威”号货轮由大连港驶往广州港。7月20日，接近上海港时遭遇海上风暴，其间货轮结构遭到严重破坏，船上一批燃油泄漏进大海中。接到求救信号后，“风烟”号对“扬威”号进行了救助，使得“扬威”号脱离险境，船上大部分货物得以保全。但由于“风烟”号船员操作不当，在理算救助费用时，各方发表了下列观点，其中哪一项是合理的( )

A．“扬威”号托运人甲认为，“扬威”号并未与“风烟”号签订正式的书面合同，救助合同不能成立，因而自己不应当支付报酬
B．“扬威”号托运人乙认为，在订立救助合同时，“扬威”号船长并未征求自己的意见就在合同中约定了高额的救助费用，属于无权代理，自己有权拒绝承认该合同并不应当支付救助费用
C．“扬威”号所有人丙认为，有证据证明根据救助合同支付的救助款项明显高于实际提供的救助服务，己方有权请求法院变更救助合同
D．“风烟”号船长丁认为，己方除救助货船之外救助了20个人，这些人应当向其支付酬金

常见的有氧运动有哪些？