【托福阅读题型：the Periodic Table句子简化题】托福阅读中句子简化题是重要题型之一。根据托福阅读题型不同来进行专项练习，是短期提高托福阅读能力的有效方法。同学们需要多加练习哦!

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　　托福阅读句子简化题：the Periodic Table

　　【Paragraph 4】The structure of the periodic table appeared to limit the number of possible elements. It was　therefore quite surprising when John William Strut (Lord Rayleigh, discovered a gaseous element in 1894 that did not fit　into the previous classification scheme. A century earlier, Henry Cavendish had noted the existence of a residual gas　when oxygen and nitrogen are removed from air, but its importance had not been realized. Together with William　Ramsay, Rayleigh isolated the gas (separating it from other substances into its pure state) and named it argon. Ramsaythen studied a gas that was present in natural gas deposits and discovered that it was helium, an element whose　presence in the Sun had been noted earlier in the spectrum of sunlight but that had not previously been known on Earth.　Rayleigh and Ramsay postulated the existence of a new group of elements, and in 1898 other members of the series　(neon, krypton, and xenon) were isolated.(Development of the Periodic Table)

　　Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?　Incorrect choices change the meaning in important ways or leave out essential information.

　　○Ramsay found evidence of helium in the spectrum of sunlight before he discovered that the element was also　contained in natural gas deposits on Earth.

　　○Ramsay thought he had discovered a new element present in natural gas deposits, but he was wrong since that　　element had been previously observed elsewhere on Earth.

　　○After Ramsay had discovered a new element, called helium, in natural gas deposits on Earth, he also found　evidence of its presence in the Sun.

　　○Ramsay later discovered that helium, an element that was already known to be present in the Sun, was also　present in natural gas deposits on Earth.