问题 选择题

下列说法正确的是(  ).

A.两支铅笔靠在一起,自然光从笔缝中通过后就成了偏振光

B.偏振光可以是横波,也可以是纵波

C.因为激光的方向性好,所以激光不能发生衍射现象

D.激光可以像刀子一样切除肿瘤

答案

答案:D

两支普通铅笔靠在一起,中间的缝远远地大于光的波长,因此,光从中通过时不会成为偏振光;光是横波,偏振光也是横波;激光也是光,因此激光具有光的特性,能够发生衍射现象;激光有很多用途,其中包括做手术,切除肿瘤.

阅读理解

About twenty of us had been fortunate enough to receive invitations to a film-studio(影棚)to take part in a crowd-scene. Although our "act" would last only for a short time, we could see quite a number of interesting things.

We all stood at the far end of the studio as workmen prepared the scene, setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie-camera was wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in "snow". Two more fans were turned on, and a "strong wind" blew through the trees. The picture looked so real that it made us feel cold.

The next scene was a complete contrast(对比).The way it was filmed was quite unusual. Pictures taken on an island in the Pacific were shown on a glass screen. An actor and actress stood in front of the scene so that they looked as if they were at the water's edge on an island. By a simple trick like this, palm trees, sandy beaches, and blue, clear skies had been brought into the studio!

Since it was our turn next, we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film ”Stars”!

小题1:Who is the author?

A.A cameraman.

B.A crowd-scene actor.

C.A film director

D.A workman for scene setting小题2:What made the author feel cold?

A.The heavy snowfall.

B.The low temperature

C.The man-made scene..

D.The film being shown小题3:What would happen in the "three minutes" mentioned, in the last paragraph?

A.The next scene would be prepared.

B.More stars would act in the film.

C.The author would leave the studio.

D.A new scene would be filmed.

问答题 案例分析题