我国环境保护的基本方针是什么？

患者男性，46岁，反复发作腹泻、左下腹痛伴脓血使4年余，食欲下降，多次大便细菌培养阴性，反复抗生素治疗无效，否认结核病史及急性细菌性痢疾病史。查体：T37.5℃，面色苍白，心肺（-），腹平软，左下腹轻压痛，无反跳痛，未及包块，Hb76g/L，WBC12.5×10⁹/L，其中N75.8%.ESR56mm/h，CRP36mg/L，PPD试验（1：10000）（-），大便常规：RBC（+），WBC（-），多次大便细菌培养均阴性。血CEA、CA-199及CA-125均正常水平。X线钡灌肠示乙状结肠及直肠黏膜粗乱及颗粒样改变，多发性浅溃疡，结肠袋消失，肠壁变硬，肠管缩短、变细。

为协助诊断，可采用的核医学检查方法有（）。

A.⁶⁷Ga显像

B.^99mTc-MIBI

C.¹¹¹In-Oxine-WBC显像

D.^99mTc-AGAB显像

E.^99mTc-IgG显像

F.¹⁸F-FDG

2002年诺贝尔物理学奖中的一项，是奖励美国科学家贾科尼和日本科学家小柴晶俊发现了宇宙X射线源．X射线是一种高频电磁波，若X射线在真空中的波长为λ，以h表示普朗克常量，c表示真空的光速，以E和m分别表示X射线每个光子的能量和质量，则（　　） A．E=，m=0 B．E=，m= C．E=，m=0 D．E=，m=

按短路电路的对称性来分，下列选项中属于对称性短路的是( )。

A．单相短路
B．两相短路
C．三相短路
D．两相接地短路

下列哪项不符合IMO对船舶稳性衡准的最低要求（）

A.倾角30°处的复原力臂不小于0.30m

B.大复原力臂对应角（权限静倾角）最好大于30°，至少不小于25°

C.满足天气衡准要求（仅适合于船长等于或大于24m的船舶）

D.稳性高度GM应不小于0.15m

B

Each year there is an increasing number of cars on roads and street are millions of new cars are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads of filling cars with gas. Americans won’t live without cars!
Most Americans find it hard to think what life would be without a car. However some have realized the serious problem of air pollution by cars. The polluted air is poisonous(有毒的) and dangerous to health.
One way to get rid of(排除)the polluted air is to build a new kind of car. That’s what several of the large car factories are trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.
Another way is to take the place of the car engine(发动机) by something else. Engineers are now working on some new cars. Many makers believe that it will take years to develop a practical model that pleases man.
To prevent the world from being polluted by cars, we’ll have to make some change in the way many of us live. Americans, for example, have to cut down on the number of their cars. They are encouraged to travel and go to work by bike. Riding a bike is thought to help keep the air clean.
But this change does not come easily — a large number of workers may find themselves without jobs if a car factory closed down. And the problem of air pollution would become less important than that of unemployment(失业).
Although cars have brought us a better life, they have also brought us new problems.

The writer wants to tell us that ______.

A．riding a bike is the only way out

B．the number of cars must be cut down

C．man won’t live without cars

D．cars bring us not only a better life but also serious problems