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.
时（T为交流的周期），原线圈中的电流瞬时值为0.03A．变压器的原、副线圈的匝数比为（ ）
：3