请教几道prep语法题

190.
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The thirteen original British colonies in North America, some formed as commercial ventures, others as religious havens, each had a written charter that set forth its form of government and the rights of the colonists.

A. some formed as commercial ventures, others as religious havens, each had a written charter

B. some being formed as a commercial venture, others as religious havens, all of which had written charters

C. some that formed as commercial ventures, others as religious havens, all had written charters

D. with some being formed as a commercial venture, others as religious havens, all had a written charter

E. with some formed as commercial ventures, while others as religious havens, each had a written charter

Answer: A

E 错在哪里？加了with

159.
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The first detailed study of magpie attacks in Australia indicates that by the time they had reached adulthood, 98 percent of men and 75 percent of women born in the country have been attacked by the birds

A. by the time they had reached adulthood, 98 percent of men and 75 percent of women born in the country have been attacked by the birds

B. by the time they reach adulthood, 98 percent of men and 75 percent of women, who were born in the country, had been attacked by the birds

C. by the time they reached adulthood, 98 percent of men and 75 percent of women born in the country had been attacked by the birds

D. 98 percent of men and 75 percent of women that were born in the country were attacked by the birds by the time they reach adulthood

E. 98 percent of men and 75 percent of women who were born in the country, by the time they reached adulthood had been attacked by the birds

Answer: C

E 和C长得也差不多啊，不知道差在哪里呢？

166.
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The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic peoples has been established by carbon dating, but what is much more difficult to determine are the use to which primitive peoples put the caves, the reason for their decoration, and the meaning of the magnificently depicted animals.

A. has been established by carbon dating, but what is much more difficult to determine are

B. have been established by carbon dating, but what is much more difficult to determine are

C. have been established by carbon dating, but that which is much more difficult to determine is

D. has been established by carbon dating, but what is much more difficult to determine is

E. are established by carbon dating, but that which is much more difficult to determine is

Answer: D

句末一串名词谓语动词不应该用are么