化学物质不易进入中枢神经系统的原因。

I am a fan of Liu Qian.            his magic             his humor attracts me. [ ]

A. Both… and

B. Either…or

C. Neither…nor

D. Not only… but also

A new study done by the Higher Education Quality Council of Ontario （HEQCO） shows that it doesn't make much of a difference that parents reward their children with cash for their better marks.

Many parents have offered cash to their children in the hope that it would improve marks and possibly raise their children's interest in achieving higher marks．

The study, conducted by researchers from the University of Toronto （UT） and the Massachusetts Institute of Technology （MIT） to learn more about the potential for financial encouragement as motivation for improved marks, involved first and second year students receiving financial aid in 2008-2009 at the University of Toronto Scarborough．

The top students participating in the study who said they were "very concerned" about having enough money to complete their degrees were to receive $100 for getting a grade of 70 per cent for each one-semester course, plus $20 for every percentage point beyond that．It was imaginable that a student could earn as much as $700 for achieving 100 percent in a course．

Harvey Weingarten, president and CEO of HEQCO said, "In its efforts to help disadvantaged students by exploring the idea of paying them to attend school, the Toronto District School Board （TDSB） is asking the same question many other districts are asking about how to improve student participation and performance．Our study and others to date indicate that this practice has little effect if any in those situations where it has been tested．"

The authors of the study suggest that ineffective study habits may be a barrier to academic achievement and that the real problem may be more a lack of academic preparation than a lack of effort or motivation．They note that the availability of peer （同伴） advising does not appear to have helped greatly．They conclude that other potential avenues to improving performance, or other approaches of teaching, are needed at the high school and postsecondary levels．

小题1:If a student gets a grade of 85% in a course, he will get _____．

A．$100

B．$300

C．$400

D．$700小题2:The underlined words "this practice" in Paragraph 5 refer to _____．

A．improving student participation

B．seeking help from different districts

C．paying disadvantaged students to attend school

D．testing student performance in the same district小题3:The real problem with student participation and performance is most probably a lack of____．

A．academic preparation

B．effort or motivation

C．teaching methods

D．peer advising小题4:What is mainly discussed in the passage?

A．Many parents have offered cash to their children．

B．Many first and second year students receive financial aid．

C．Ineffective study habits lead to poor academic achievement．

D．Rewarding students with cash for good grades has little effect

《 * * 党宣言》的发表标志着——

经过预冷器的空气是引自（）

A.发动机外涵的风扇空气

B.发动机压气机的压缩空气

C.外界大气

与大多数物质相反，碳酸钙垢随温度升高会结垢更多。