洋地黄中毒的心电图变化最常表现为（）。A．室性期前收缩 B．ST-T呈鱼钩样改变 C

函数y= 1 x-1 中，自变量x的取值范围是______．

带电粒子射入一固定的带正电的点电荷Q的电场中，沿右图中实线轨迹从a运动到b，a、b两点到点电荷Q的距离分别为ra、rb（ra＞rb），b为运动轨迹上到Q的最近点，不计粒子的重力，则可知（   ） A．运动粒子带负电 B．b点的场强大于a点的场强 C．a到b的过程中，电场力对粒子不做功 D．a到b的过程中，粒子动能和电势能之和保持不变

Part 4

Questions 26-45

·Read the following passage and decide which answer best fits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.
Participation (26) high school sports is not a constitutional right. (27) , it is a privilege, paid for by taxpayers, open to students who promise to (28) certain conduct requirements on and off the field. One of these promises is to (29) from using drugs. Drug use is a serious problem among high school students. Studies show that as many as 500, 000 high school students use muscle-pumping, life-destroying substances such as steroids. Many more use illegal drugs, (30) cause discipline problems and (31) the stage for lifelong (32) .
Drug testing works to (33) and identify use. That is why drug testing is required to compete in the Olympics, the National Collegiate Athletic Association and the National Football League. (34) drug testing was instituted by these organizations, use of performance- (35) drugs has been greatly reduced. We should want (36) in schools.
Indeed, many athletes (37) testing programs, and no wonder. Without testing, athletes have to choose between drug use and a competitive disadvantage (38) the field.
Those who challenge the need for drug testing may be forgetting (39) it is like be an adolescent. Peer pressure is enormous, and one of the few effective counter-weights is the fear of being caught. More importantly, once drug use is (40) , a school can (41) to the student before he or she gets addicted or arrested.
For 25 years, public schools (42) by federal judges and civil libertarians, with results everyone can see. It is time (43) decisions on how to run public schools locally (44) officials. There is nothing unconstitutional about asking those who gain the advantages of school-sponsored athletics to contribute to the safety of other players, the integrity of the game and their own well-being. The Supreme Court should leave these programs (45) .

A．Since

B．After

C．When

D．While

哪一项不是乳牙拔除禁忌证（）

A.血液病

B.急性感染

C.严重心脏病

D.智障不合作

E.严重的口腔黏膜疾病

软件工程的出现是由于( )。

A．程序设计方法学的影响

B．软件产业化的需要

C．软件危机的出现

D．计算机的发展