HVDC Light是（）提出的柔性直流输电技术命名。

A.提供

B.不提供

C.增加

D.其他三个选项都不是

A.IGBT

B.均压电路

C.触发电路

D.散热设备

A.北京市

B.上海市

C.天津市

D.重庆市

A.直流控制系统参数调整

B.全站二次系统的同步与对时

C.故障、异常下的监视与处理

D.全站设备监视报警信号的汇总

A.自动切换为频率控制

B.自动切换为交流系统电压控制

C.自动切换为电压控制

D.自动切换为直流系统电压控制

Something looks yellow because it ______.

A．absorbs mostly yellow light

B．reflects mostly yellow light

C．absorbs all light

D．reflects all light

eople who use books and pens every day have to be especially careful about the way the light shines on their work.

Every house gets its light either from daylight through the windows—which is the best to use—or from lamps or electricity;but whichever kind of light it is, the way it shines toward our book or work is a matter of great importance to the eyes.

Take a book，sit with your back toward the window，and try to read. Your shadow(影子)falls all over the page and makes it almost as bad for your eyes as if you were in a dark room.

Now turn around and face the window. The page is in the shadow again,while the bright light is in your eyes.

Try sitting with your right side toward the window. This is very well for reading, but if you were writing,the shadow of your hand would fall across the page and bother(打撹)you a little.

There is just one other way：sit with your left side to the window. Now everything is perfect for reading and for writing,too.

Whatever kind of light is in the room,the rule about the right to sit is always the same.

Which of the following is true？

A.How the light shines on our work is of much importance

B.The way the light shines on your work makes no difference

C.We needn’t care about where the light comes from

D.People can write or study under a light that comes from any direction

When you sit with your face towards the window,____.A.your shadow falls on your book

B.your book is in a shadow

C.the light is still dark

D.the light is on your page

The best way both for reading and for writing is to_____.A.sit facing the light

B.let the light shine from your back

C.sit with your right side towards the light

D.have the light come ffrom your left

请帮忙给出每个问题的正确答案和分析，谢谢！

A.shed slight on

B.shed light on

C.shed light to

D.throw light to

Why do the American doctors think of using laser light to treat heart disease？

A．Beeause laser light is quite powerful．

B．Because laser light is penetrating．

C．Because laser light can destroy the blocking materials in human’s artery．

D．Because laser light can travel through the human body．