人民代表大会制度是我国的根本政治制度。人民民主专政是我国的国体。 () A．正确

农业上用生长素类似物2，4—D进行麦田除草的原理是：[ ]

A．高浓度生长素类似物促进杂草衰老

B．高浓度生长素类似物抑制杂草生长

C．低浓度生长素类似物抑制杂草生长

D．高浓度生长素类似物促进小麦生长

《中华人民共和国合同法》第二百二十九条规定：租赁物在租赁期间发生所有权变动的，它对租赁合同的效力( )。

A．不影响

B．影响

C．增强

D．减弱

Damage to Ozone Layer Gets Worse

In the middle of winter, when snow is falling in many parts of the United States, scientists have sounded a warning to people who plan to spend many hours in the sun this summer．The warning: The sun's summertime rays are more dangerous than once thought.

A team of scientists from 80 nations recently reported to the United Nations that a layer of ozone（臭氧层）in the atmosphere, which protects humans from harmful levels of ultraviolet（紫外线）radiation, will be thinner over the United States this summer．The thinner layer allows more ultraviolet rays from the sun to reach Earth．The extra amount of ultraviolet radiation could cause an increase in the number of cases of skin cancer.

Scientists first became concerned about the layer in the mid-1980s when a hole was discovered in the layer above Antarctica during the winter．The hole was caused in chemicals used in refrigerators and air conditioners．When these chemicals are sent out into the atmosphere, they produce gases that destroy the ozone.

Concern about the protective ozone layer rose more recently when data from satellites and ground stations showed that ozone levels were dropping over areas other than Antarctica．Low ozone levels were recorded in the spring and summer over the United States and over other populated areas in the world.

Although many countries have already begun stopping the use of ozone-destroying chemicals, the new findings are expected to advance the timetable for a total ban of the chemicals.

小题1:The scientists have observed the ozone layer ______．

A．since 1980

B．since last winter

C．for more than 20 years

D．for about one year小题2:The ozone layer in the atmosphere can ______.

A．do a lot of good to human beings in many ways

B．protect humans from diseases caused by bad weather

C．do a lot of harm to human beings in the summer-time

D．protect humans from harmful levels of ultraviolet radiation小题3:Scientists first found that there was a hole in the ozone layer ______.

A．above Arctic during the winter in the mid-1980s

B．above Antarctica during the winter in the mid-1980s

C．over somewhere in the north of the equator in 1980

D．over the USA in the summertime in the mid-1980s小题4:The damage to the ozone layer was caused by ______.

A．the changeable weather

B．ozone-destroying chemicals

C．chemicals from refrigerators

D．chemicals from air conditioners

燃料燃烧是一种化学反应，一般需要在加热的条件下进行，达到可燃物的燃点时燃烧发生，加热的作用是使反应物的温度升高．从物理学的角度看，加热是通过______的方式增加物体的内能．反应物的温度越高，反应物分子运动越______，当达到一定程度时，燃烧即可发生．反应物的温度越高，燃烧反应的速度越快．

下列函数定义中，会出现编译错误的是( )。

A．max(int x,int y,int * { *z=x＞yx:y; }

B．int max(int x, { int z;z=x＞yx:y;return z; }

C．max(int x,int { int z;z=x＞y x:y; return(; }

D．int max(int x,int { return(x＞y x:; }