PREP07 SC 3，关于逻辑主语。。求讲解

冷月无声5555

Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil, their
descendants, popularly known as killer bees, had migrated as far north as southern Texas.

(A) Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil,
(B) In less than 35 years since releasing African honeybees outside Sao Paulo, Brazil,
(C) In less than the 35 years since African honeybees had been released outside Sao Paulo,Brazil,
(D) It took less than 35 years from the release of African honeybees outside Sao Paulo, Brazil,when
(E) It took less than the 35 years after the time that African honeybees were released outside Sao Paulo, Brazil, and then  

A正确, after + n.结构避免了逻辑主语问题;
B选项的解答：since releasing放在句首,逻辑主语等于句子的主语their descendants,    不符合逻辑;
                  请问这里的逻辑主语到底是什么啊。。好晕，求讲解！灰常感谢！！！

rylstar01

我是这么理解的。
1）A中，After+n.是结构避免了逻辑主语问题，是说明这个句子你不需要考虑逻辑主语了，因为这个句子已经完整了，其的主语就是release了。意为“在release这件事之后，their descendents ...balabala”
2）B中，由于since+ v-ing置于句首，省略了主语，那么你就得考虑其的逻辑主语是谁，然后发现是their descendents。假如这个逻辑主语是正确的，那么就是their descendent release African honeybees，就显示出了其的逻辑不合理了。
3）小建议，是否需要考虑逻辑主语，取决于其的句子结构是否完整清晰。（刚想的，正确与否还得后面的高手帮忙斧正）

kiwifoodtown

LS的解释有点道理。