已知椭圆方程为x2a2+y2b2=1(a＞b＞0)，它的一个顶点为M（0，1），

光在不同介质中的传播速度一般不同，光在             中的传播速度最大，在我们的计算中取             m/s．

-Did your manager phone you again the next day?

-No,it was a fortnight       he gave me a second call. [ ]

A.when

B.since

C.before

D.that

The mobile phone has been a part of our lives since the 1980s. It enables us to stay in contact with our family and friends at all times and in most areas. However, because of the quick acceptance and extensive usage of mobiles in our lives, we have missed out on an important step, namely, the appropriate (恰当的)use.

Driving a car  

Do not use your phone while you are driving ! You could concentrate on your conversation and forget to look where you are going, or you could take your eyes off the road to look at the phone’s display or to press in a number. Either way, you could cause a terrible accident.

In a restaurant

There is probably nothing more annoying than a diner receiving or making a call near you when you are in a restaurant. The icy glares you receive should be warning enough that it is not appreciated. Turn you phone off and enough that it is not appreciated. Turn you phone off and use your message service to return calls after you leave.

At the cinema

Do not give way to the desire to call a friend if the film is boring, or if you want to find out what happens. You could become the target of all the angry cinema customers.

At the theatre

There is no more icy glare than that of a theatre goer who has paid a lot of money to see a show and hears your phone playing a tone. It goes without saying that you will be seen as a socially unacceptable person in this situation.

In hospitals

This is probably the most important place to make sure your phone is switched off. Your phone can disturb life-saving electronic equipment in hospitals, so it is necessary that your phone is switched off before you enter.

On planes

Your phone might disturb navigational equipment and cause a horrible accident so you should switch it off before boarding a plane.

小题1:According to the passage, the most annoying thing in a restaurant is that __________.

A．you receive icy glares

B．a nearby diner is answering a phone call

C．you have to use the message service

D．you can not return calls until after you leave小题2:Which of the following statements is NOT true ?

A．Theatre goers will not give you icy glares when they hear your phone.

B．When switched on in hospitals, mobile phones could endanger patients’ lives.

C．Passengers should switch off the phones before getting on a plane.

D．Pressing in phone numbers when driving could lead to traffic accidents.小题3:The passage mainly describes __________.

A．different functions of mobile phones

B．the overuse of mobile phones on some occasions

C．some areas where message service is forbidden

D．the proper use of mobile phones in some public places小题4:What does the underlined word “concentrate on” mean in the article? It means ______.

A．make something stronger

B．carry on

C．pay particular attention

D．think something clearly

目前新能源开发利用方面，标准制定主要集中在（）并网，许多国家和地区都针对各自实际情况制定了并网标准。

A.光伏发电

B.风力发电

C.光热发电

D.生物质发电

催化剂过滤器预涂的目的是（）。

A、减小流动阻力

B、增大阻力，避免切入时流量过大

C、形成滤饼，避免催化剂漏出

D、增加过滤器内催化剂浓度，提高加氢效率