（2） sum of any=0 1+-1=0 但是1和别的数加起来不能=0，所以（2）使得所有数字只能是0

OG18-SC714-E选项的解析中：E选项：rob和make是alter的两个并列的后果，两个并列是成分用and连接时，and身前不能有逗号。例如，一般我们说：
(1) James and I went to New York.
我们不说：
(2) **James, and I went to New York.
当投资100刀和每年能挣2刀并列时，应该写为：
I invested $100, holding 3 share, and could earn $2 per year.
此时不能写为：
I invested $100, and I held 3 share and could earn $2 per year.
可是本题中DE选项又出现and前后加逗号没有问题，这是什么原因呢毕出老师？ 有很多这样的点让我很迷糊，是我哪里理解错了吗，本题DE选项中两个that引导的从句不是也是并列的成分么。还是说如你上课讲的判断原则：看大不看小，既然AE选项成分差异能看出来，就不必纠结于and前后的这个问题，但我还是想知道and前后加逗号这个知识点要不要掌握呀

切点也是intersect

因为硬币后来没发现所以就是有地震了？？？这是什么鬼逻辑

我理解的"excessively restrictive control"是指control“过度局限”，就是说“过度局限”的control也许不会包括所有的有害物质。所以为了显示control并不局限，就要说明有害的物质都被包括进去了。
不知道这样理解对不对。同时觉得楼下的解释也合理。感觉精神错乱了。

是灭绝标志了时代的结束。D选项中，事件本身和事件的影响不是并列的关系，不用and

1)问什么不能n是奇数m是偶数呢

这个题有人可以帮忙解答下么。。

之前看过一个搭配low enough to ，在这里一下想起来了，fast enough to是一个类型。就剩下BE选，E意思不对。concern的不是possibility而是整件事。

so, choice (a) (as well as (c) and (e)) implies that the bird itself is "stored long enough to have rotted" -- an interesting idea, but certainly not the intended meaning of the sentence.

there's also the problem with "if [participle]" -- a modifier that, by convention, refers to the SUBJECT of the sentence (not the proximate noun).
for instance:
Animal 1 will attack animal 2 if injected with enough of the hormones related to aggression.
--> in this sentence it is animal 1, not animal 2, that is being injected with hormones.

A scrub jay tends not to bother to recover a perishable treat if stored long enough to have rotted. if从句主语和主句一致，所以是这个鸟，所以语意错误。

想请问A为什么错呢 看到OG上的解释是[giving...]的部分illogically modifies the whole preceding clause, rather than [satellite]. 但是giving 的逻辑主语不是应该是a new satellite吗？ 谢谢大家了

b容易选错

对e选项不太理解

建立因果联系，要包括文中重要的成分

看不出a错哪里。a的意思我理解是“在1910-1911年那次回归引起的”。和前文In no other historical sighting did Halley's comet caus完全对应啊

* if you say "subject + clause + BY VERBing", then "by VERBing" must explain HOW the main clause occurred.
* if you say "subject + clause + IN VERBing", then subject + clause must be an ACTUAL PART of the action of VERBing.
"as well as ..." is a MODIFIER, and thus can be stricken from the sentence without affecting the surrounding grammar，"as well as" is NOT a replacement for "and".

lie lied lied 说谎
lie lay lain 平躺,位于
lay laid laid 放置,下蛋