Before scientists learned how to make a synthetic growth hormone, removing it painstakingly in small amounts from the pituitary glands of human cadavers.
(A) scientists learned how to make a synthetic growth hormone, removing it painstakingly
(B) scientists had learned about making a synthetic growth hormone, they had to remove it painstakingly
(C) scientists learned how to synthesize the growth hormone, it had to be painstakingly removed
(D) learning how to make a synthetic growth hormone, scientists had to remove it painstakingly
(E) learning how to synthesize the growth hormone, it had to be painstakingly removed by scientists
答案是C， D为什么错。before 后加ving, 逻辑主语是句子主语 scientists. Og13-90 题有例子为证. after falling over....逻辑主语是which定语从句修饰的名词，profits
og 13 - q90
The results of the company’s cost-cutting measures
are evident in its profits, which have increased 5 percent during the first
3 months of this year after falling over
the last two years.
Q32. p2-sc 28. (25890-!-item-!-188;#058&002817)
In 1997, despite an economy that marked its sixth full year of uninterrupted expansion with the lowest jobless rate in a quarter century, the number of United States citizens declaring themselves bankrupt has jumped by almost 20 percent, at 1.34 million.
(A) declaring themselves bankrupt has jumped by almost 20 percent, at
(B) declaring themselves bankrupt jumped by almost 20 percent, to
(C) who declared themselves bankrupt has jumped by almost 20 percent, to
(D) who declared themselves bankrupt jumped almost by 20 percent, at
(E) to declare themselves bankrupt jumped almost by 20 percent, at
答案是B. 其他点明白。不明白的地方是为什么用declaring。不用 who declared. 根据PREP08语法笔记 P38页198题，ING 修饰与 that从句修饰名词的区别， ING 强调笼统不确定时间，抽象、客观、多次、重复行为。定语从句强调具体时间具体动作，以及动作的一次性。这里，1997年，宣布破产的美国公民人数增多到。。。，难道不是具体时间，一次性的行为吗，为什么用declaring - 不确定时间，多次，重复行为?
Q33. p2-sc 29. (26032-!-item-!-188;#058&002964)
Unlike many United States cities, where a river is no longer the focal point of urban life, the river in San Antonio winds through the middle of the business district, and the River Walk, or Paseo del Rio, is the city's most popular attraction.
(A) Unlike many United States cities, where a river is no longer the focal point of urban life, the river in San Antonio
(B) Unlike the river in many cities in the United States, which is no longer the focal point of urban life, in San Antonio the river
(C) Today the river in many cities in the United States is no longer the focal point of urban life, unlike San Antonio, where it
(D) In few United States cities today, a river is the focal point of urban life, but the river in San Antonio
(E) No longer do many cities in the United States have a river as the focal point of urban life, but in San Antonio the river
答案是E。 实在不明白E倒装 为什么对。如果说B错在 unlike the river in many cities in US, in SA the river..比较不对称， 那D为什么不对: a river is the focal point, but the river in SA is the city's....没觉得有什么问题。