the philosopher's stone" Alchemists searched in vain for this substance for several hundred years Alchemy was studied widely in Europe during the twelfth and following centuries, and attracted the attention of many learned men Though they were doomed to fail in their attempts to make gold their work led to the growth of a great deal of new chemical knowledge and of methods of making experiments. By the first half of the sixteenth century, the aim of the alchemists had changed from the making of gold to the making of medicines. In particular they sought a fanciful substance called“ the elixir(长生不老药) of life" a powerful medicine which was to cure all ills, and which some people thought would turn out to be the same substance as the philosopher's stone". This phase of chemistry lasted till about 1700 16.The practical basis of several modern chemical industries was developed from A. Asian astrologers B. Greek philosophers C. Alexandrians D. the ancient Egyptians 17.It was the arab conquerors who A. studied alchemy in the eventh century B introduced alchemy to Western Europe C spread alchemy to Egypt D. carried out alchemical experiments in Spain 18.The greatest Arab alchemist Jabir ibn Hayyan A translated two important books on alchemy from Latin in the 13th century B. extended the greek theories about the "elements" c. was of t he opinion that all metals were made up of the same four elements D. gave the name "the philosophers stone "to a mysterious substance 19. From the twelfth to the eighteenth century“the philosopher’s stone”.Alchemists searched in vain for this substance for several hundred years. Alchemy was studied widely in Europe during the twelfth and following centuries,and attracted the attention of many learned men.Though they were doomed to fail in their attempts to make gold,their work led to the growth of a great deal of new chemical knowledge and of methods of making experiments.By the first half of the sixteenth century,the aim of the alchemists had changed from the making of gold to the making of medicines.In particular they sought a fanciful substance called “the elixir （长生不老药）of life”,a powerful medicine which was to cure all ills,and which some people thought would turn out to be the same substance as “the philosopher’s stone”.This phase of chemistry lasted till about 1700. 16.The practical basis of several modern chemical industries was developed from ____. A. Asian astrologers B. Greek philosophers C. Alexandrians D. the ancient Egyptians 17.It was the Arab conquerors who ____. A. studied alchemy in the seventh century B. introduced alchemy to Western Europe C. spread alchemy to Egypt D. carried out alchemical experiments in Spain 18.The greatest Arab alchemist Jabir ibn Hayyan ____. A. translated two important books on alchemy from Latin in the 13th century B. extended the Greek theories about the “elements” C. was of t he opinion that all metals were made up of the same four “elements” D. gave the name “the philosopher’s stone ” to a mysterious substance 19.From the twelfth to the eighteenth century ____