The following sentences are from speeches given by Marie Curie. Select the word or words that best complete the sentence.
1. The scientific history of radium ______ beautiful.
2. Radium is no more a baby but the conditions of the discovery were somewhat peculiar, and so it is always of interest ______ them and to explain them.
to have remembered them
3. Professor Curie and I worked at that time in the laboratory of the school of Physics and Chemistry where Professor Curie ______ his lectures.
4. All the elements ______ such radiation I have termed radioactive.
5. I wanted ______ if there were other elements, giving out rays of the same kind.
6. If we ______ a practical point of view, then the most important property of the rays is the production of physiological effects on the cells of the human organism.
7. And in that way it has been proved that the radioactive elements are constantly ______ and that they produce at the end ordinary elements, principally helium and lead.
8. Then I ______ that there should be in the minerals some unknown element having a much greater radioactivity than uranium or thorium.
9. Other radioactive elements ______ since: actinium (Debierne), radiothorium and mesothorium (Hahn), ionium (Boltwood), etc.
have been discovered
had been discovered
10. In chemical terms radium ______ little from barium.
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