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题库 / Prep2007E2-SC-21
Before scientists learned how to make a synthetic growth hormone, removing it painstakingly in small amounts from the pituitary glands of human cadavers.
scientists learned how to make a synthetic growth hormone, removing it painstakingly
scientists had learned about making a synthetic growth hormone, they had to remove it painstakingly
scientists learned how to synthesize the growth hormone, it had to be painstakingly removed
learning how to make a synthetic growth hormone, scientists had to remove it painstakingly
learning how to synthesize the growth hormone, it had to be painstakingly removed by scientists
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choice e is wrong, because it starts out with an initial modifier lacking a subject; such modifiers MUST modify the noun IMMEDIATELY FOLLOWING the comma. in the case of choice e, this would mean that 'it' (referring to the hormone itself) learned how to make the hormone. that's crazy.
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