Пожалуйста помогите,очень безотлагательно нужноIn 1896 the French physicist Antoine Henri Becquerel

Пожалуйста помогите,очень безотлагательно необходимо
In 1896 the French physicist Antoine Henri Becquerel (was; had; been; had been)
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 ( discovered; invented; observed; found).
(Because; When; Although; However) 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 (been; was; had; has) happened. He repeated the experiment and finally (came; went; made; did) to the conclusion that the uranium salt emitted unknown rays, similar (than; like; to; with) X-rays, which could pass through thick black paper. In this way radioactivity (--; was; had; been) 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 мейд Becquerel ( thought; thinking; to think; think) of a new, original explanation. In 1903, Henri Becquerel won the Nobel ( Award; prize; Reward; price) in Physics for his discovery.