Ex.10. Read the text about the discovery of radioactivity. For gaps 1-9 choose the correct answer A-D.
THE DISCOVERY OF RADIOACTIVITY
In 1896 the French physicist Antoine Henri Becquerel 1________ investigating uranium salts. He accidentally left a bit of uranium lying on some photographic plates – glass plates which were used in photography before film was 2________.
3________ the plates were wrapped in thick black paper to protect them from light, after some time Becquerel found out that they had been exposed, just as if they had been lying in the sun. He asked himself how this 4_________ happened. He repeated the experiment and finally 5________ to the conclusion that the uranium salt emitted unknown rays, similar 6________ X-rays, which could pass through thick black paper. In this way radioactivity 7________ discovered.
The story shows some important qualities of a scientist’s mind: the desire to understand why something happens the way it does, and the imagination which made Becquerel 8________ of a won the Nobel 9________ in Physics for his discovery.