help, 3道题求解!!

winonawu

For many travelers, charter vacations often turn out to cost considerably more than they originally seemed.
(A) they originally seemed
(B) they originally seem to
(C) they seemingly would cost originally
(D) it seemed originally
(E) it originally seemed they would

这题答案是A。
B是因为时态错, 怎么解释呢?

winonawu

268. During the recession of 1973, home mortgage foreclosures resulted in tens of thousands of Americans being evicted from homes that they can no longer afford monthly payments.
(A) that they can
(B) that they could
(C) on which they can
(D) because they can
(E) for which they could

B 为什么错呢?

winonawu

41.Since chromosome damage may be caused by viral infections, medical x-rays, and exposure to sunlight, it is important that the chromosomes of a population to be tested for chemically induced damage be compared with those of a control population.

(A) to be tested for chemically induced damage be compared with

(B) being tested for damage induced chemically are compared with

(C) being tested for chemically induced damage should be compared to

(D) being tested for chemically induced damage are to be compared to

(E) that is to be tested for chemically induced damage are to be comparable with

pls some1 explain why not E .

winonawu

I need help guys..............pls

tiffany1224

1.  originally是一般过去时的标志
2.During the recession of 1973, home mortgage foreclosures resulted in tens of thousands of Americans being evicted from homes that they can no longer afford monthly payments.
(A) that they can
(B) that they could
C) on which they can
(D) because they can
(E) for which they could
如果选B 的话 应该是
During the recession of 1973, home mortgage foreclosures resulted in tens of thousands of Americans being evicted from homes that they could no longer afford. homes 作为afford的宾语。
但是在原句中afford已经有了宾语：afford monthly payments.所以需要一个for which， 不知道有没有讲清楚啊啊啊

3.it is important that 要用虚拟语气的 选项中只有A用对了虚拟语气
况且E选项that is to be的that从句可以是修饰population