引起机械性肠梗阻最常见的原因是（）。A．腹膜后巨大血肿 B．肠壁肿瘤 C．肠蛔虫症

阅读理解。

     Good health needs good sleep. Going to bed before you're tired. No eating or reading in bed. Go to

bed at the same time before midnight and get up at the same time. Your body likes routine (常规) for a

good night's sleep.

     Studies show that a cold or flu virus (病毒) can live on our hands for long. So wash all parts of your

hands frequently with soap and water. For more ways to prevent the spread of flu, please call the Health

Line at 1800 848 1313.

     Brush your teeth twice a day and visit the dentist at least once a year. The mouth is a mirror of

disease. The oral examination is not only for the health of teeth, but the whole body. For more of it,

please visit www. mydr. com. au.

     Studies have shown that many diseases have something to do with little or no physical (身体) activity.

Try to do it for 30 minutes a day, 5 days or more a week. For more information, please call the Health

Line at 1800 438 2000.

1. If you want to get a good sleep, you'd better _____.

A. go to bed after you're tired      

B. go to sleep at midnight

C. follow the bedtime routine      

D. eat something or read in bed

2. To prevent from catching a cold or flu, it's good for you _____.

A. to clean your fingers often      

B. to brush your teeth twice a day

C. to get up early every morning    

D. to wash all parts of your hands

3. You should visit the dentist at least once a year, because _____.

A. the oral examination is necessary      

B. you don't often brush your teeth

C. some diseases may be in the mirror    

D. you don't have a good night's sleep

4. Studies have shown that many diseases have something to do with _____.

A. having no oral examination      

B. washing hands with cold water

C. sleeping too late sometimes      

D. doing little physical activity

5. If you want to learn more about the flu, you can _____.

A. visit www. mydr. com. Au      

B. call the Health Line at 1800 848 1313

C. visit the dentist in your place    

D. call the Health Line at 1800 438 2000

A、B、C、D四人的职业分别是律师、医生、教师、公务员。B比医生的工资高，公务员比律师的工资低。教师比医生的工资低，C比D的工资高，B不懂法律，A工资最高。由此可知C是：

A．律师
B．医生
C．教师
D．公务员

Today, computers are really helpful. They ____ everywhere.[ ]

A. use

B. are used

C. used

D. were used

肾脏中调节血压的物质是

A．醛固酮

B．促红细胞生成素

C．肾素

D．谷氨酰胺酶

E．碳酸酐酶

斯金纳把行为分为两类，它们分别是（）。

A．学习行为和操作性行为

B．刺激行为和反应行为

C．应答性行为和操作性行为

D．操作性行为和反应行为