usher...into
usher in

substitute可以作不及物+for

句意啊，如果按照A的话but后面应该接in xxx

the "rule" is:
* POSSESSIVE NOUN with NON-POSSESSIVE PRONOUN is NOT OK.
BUT
ALL OTHER COMBINATIONS are ok.
i.e.
possessive noun with possessive pronoun is ok.---所以C的指代没有问题
non-possessive noun with non-possessive pronoun is ok.
non-possessive noun with possessive pronoun is ok.

C不可以么

education和job training不属于economic类，C、E虽然也在反驳fact的观点，但依然是在说economic

when you have an INITIAL MODIFIER THAT'S NOT A CLAUSE (i.e., it doesn't have its own subject and verb), then it must modify the immediately following noun. in choice (e), which implies that lake baikal itself is somehow "more than all the North American Great Lakes combined".
that doesn't make sense.

C选项：平均每一英里的花费上，那些坐飞机的人比用其它交通方式的人花费了更多。本选项有些迷惑性。我们从推理文段中无法得知几种交通方式行进的英里数，因此，平均每一英里的花费就更加没法计算了。
现实的例子：国际航班，可能费用高，但里程特别长，除出来 平均没英里花费可能反而很低


D选项：Correct. 总的来说，不坐飞机旅行的人们比那些坐飞机旅行的人们有更低的平均花费。

C:平均费用=总费用/路程，但文中没给出路程
D：列等式：因为飞机总费用占一半，所以飞机总费用=其他交通工具总费用
而总费用=平均费用*人数，有题可知，其他交通工具总人数>飞机总人数
所以：飞机平均费用>其他交通工具平均费用

The entire phrase "more (water) than all the North American Great Lakes combined" is an appositive, a noun phrase used to modify another noun phrase.

等差数列

方案说需要看医生才让请假，A选项中是说如果生病现在更可能说是需要看医生的，但是请病假的总人数不一定会增加。比如以前请假的有n人，现在还是这n人，有可能是小于等于n的人病情严重，但是即使所有人都说病情严重也只有n人请假，人数并没有增加。

If you wanted to use "lower than" correctly, you would need a noun in the second part of the comparison (e.g. "2.8% is lower than the percent for last quarter).

some uncountable nouns are plural. for instance, "taxes" is a plural noun, but the concept that it represents is uncountable (taxes are not things that you can separate into one, two, three,...)

A bluff is an attempt to make someone believe that you will do something when you do not really intend to do it.--虚张声势

正常语序：
Halley's Comet did not cause such a worldwide sensation in any other historical sighting as [it did] in its return in 1910-1911

提问C选项：
1、lighting 作为名词不是也有照明的意思吗？【og没有提这个错误】
2、同问where为什么不能跳跃修饰homes；【虽然没有直接连接好】
3、OG中，C选项是"there had been less than 1 percent...."，答案指出 there had been 与was being是不正确的时态，为什么前者一定要一般过去时而不能和主句一样是过去完成时？

而不是解释为什么抱怨数增加比率比抱怨数更高。这么绕到底啥意思

中点坐标公式：x＝(x1+x2)/2,y=(y1+y2)/2

看半天才看出来是（s-t）/（t-r），把最后问题中的S看成8了

理解成插入 S+V 简单多了