cells either do sth，in which case it is A, or do another thing, in which case it is B
cells either do sth，which made it A, or do another thing, in which case it is B,前句讲荷尔蒙使得细胞成为A，后句讲在前述事例里细胞是B，语意不够平行。
case可以指代整个句子，如：The sun ejects red fire, as is the case with any star of similar mass.
因此sb do sth,in which case……里，是case指代前面的句子，which修饰case，但没有指代句子。
1、different/difference：
Right:A is different from B，A不同于B；Wrong:differences from B，来源于B的不同之处，错；Right：differences in/among sth，differences between A and B
2、伴随状语和独立主格表示条件/原因/伴随的情况/补充说明主句，不表示转折
as……as ，像某物一样……
第一个as为副词，第二个as为连词，可以接名词/形容词/状语/句子等，如：
as big as an egg;
as soon as possible;
as beautiful as before;
He was handsome as his wife was beautiful.他很帅而他的妻子很美。
in/during/over：
in强调在某个时间点，in 1997；during在……期间，强调时间范围，在某个时间范围里的每一个时间点，如Please remain seated during the performance. 演出期间请不要站起来；over强调时间的跨越，在某个时间里一直/从头至尾
ing和从句是没有区别的，two stars that orbit each other=two stars orbiting each other，
名词和ing的区别在于ing侧重于过程，名词侧重于结果，ing的动作在句子中没有明确的结束时间点，名词则有明确的结束时间点，如：
(1) Exploring the cave is taking a long time.
(2) The exploration of the cave took three days.
句(1) 中我们完全看不到“探索山洞”这件事的终止点，只是知道已经花了很长的时间了，可能还将继续花很长的时间；句(2)中，主句部分已经用过去时表明“花费了3天”，由此可知，“探索山洞”这件事已经完结了，具备明确的时间终点。
so that, 如此，以至于，包含一层因果的逻辑关系
enough to do，足够……而能够，没有因果的意思
so prevalent that it was said a squirrel could jump ，it作形式主语，事实主语时said后面的句子，某件事被传说，而不是a squirrel was said，某个人/某样东西被传说
as large as or larger than，不能说 as large or larger than，该省略无法作补足，省略错误，
C，most of planets as large as Jupiter, circling other stars，circling作伴随状语，逻辑主语只能是planets，而不是主句主语astronomers。circling修饰的句子在整个独立句里作同位语，修饰的动词(are) as large as里的large作定语修饰planets。
从本题可以看出，状语修饰最近的动作，该动作不一定作谓语动词，分词/不定式作定语的动词同样可以接修饰状语。
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两个boldface都是评论家的arguments-第一个黑体用来支持第二个黑体的结论