生态系统由四部分组成,即() A.生产者,一级消费者,二级消费者,分解者 B.生物群

题型:单项选择题 A1型题

问题:

生态系统由四部分组成,即()

A.生产者,一级消费者,二级消费者,分解者

B.生物群体、空气、土壤、水

C.生产者、消费者、分解者、非生命物质

D.生态平衡、物质循环、能量流动、信息传递

E.水圈、气圈、岩石圈、生物圈

考点:公卫执业助理医师环境卫生学环境卫生学题库
题型:单项选择题 A1型题

(1)用金属钠制取过氧化钠的化学方程式为______.

(2)呼吸面具中,Na2O2发生反应的化学方程式为______.

(3)制取氧化钠通常利用反应:2NaNO2+6Na=4Na2O+N2↑,而不采用Na在氧气燃烧的方法,采用此法的原因是______.该反应中的氧化剂是______,还原剂是______,当反应中生成气体11.2L(标准状况下)时,转移的电子为______mol.

题型:单项选择题 A1型题

Winter is dangerous because it’s so difficult to know what is going to happen and traffic accidents take place so easily . Fog can be waiting to meet you over the top of a hill. Ice might be hiding under the melting(融化的)snow, waiting ahead to send you off the road. The car coming to you may suddenly slip across the road.

Rule Number One for driving on icy roads is to drive smoothly. Sudden movements can make a car very difficult to control. So every time you either start or stop your car, increase or reduce your speed, you must be as gentle and slow as possible. Suppose you are driving with a full cup of hot coffee on the seat next to you. Drive so that you wouldn’t spill  it  .

Rule Number Two is to pay attention to what might happen. The more ice there is, the further down the road you have to look. Test how long it takes to gently stop your car. Remember that you may be driving more quickly than you think. Generally, allow twice of your usual stopping distance when the road is wet, three times on snow, and even more on ice. Try to stay in control of your car at all times ad you will not get into trouble.

小题1: How should we start or stop the car on icy roads ?

A.We should do it as quickly as usual .

B.We should do it as gently and slowly as possible .

C.We should do it as fast as possible .

D.We should do it more quickly than usual .小题2:What does the underlined word “it” refer to ?

A.A car .

B.Ice .

C.Coffee .

D.The road .小题3: Which of the following is NOT TRUE? 

A.Trafficaccidentstakeplaceeasilyinwinter.

B.Fogandmeltingsnowoftencausecaraccidents.

C.Thestoppingdistanceoniceisaslongastheusualone.

D.Inwinteryoushoulddriveyourcarwithgreatcare.小题4:What’s the best title of the passage ?

A.Dangerous Winter .

B.Foy and Ice .

C.The Rules of Driving .

D.How to Drive on the Icy Roads .

题型:单项选择题 A1型题

影响大气污染物浓度的气象因素包括()。

A.气温、气流、气压、光照

B.气温、空气离子、气压、雷电

C.气温、气流、气压、气湿

D.气温、气流、气湿、雷电

E.气温、气流、光照、空气离子

题型:单项选择题 A1型题

质量为m的木块在推力F的作用下,在水平地面上做匀速运动(如图所示)。已知木块与水平地面间的动摩擦因数为μ,那么木块受到的滑动摩擦力为下列各值的哪一个

[ ]

A.μmg

B.μ(mg+Fsinθ)

C.μ(mg-Fsinθ)

D.Fcosθ

题型:单项选择题 A1型题

于()召开的苏共二十大进一步暴露出了苏共在社会主义建设中存在的缺点和错误。

A.1955年2月

B.1955年9月

C.1956年2月

D.1956年9月

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