当时想到50、60的时候想选C的后来仔细一看（1）就足够了，（2）有点陷阱

老师，C选项的it has become precisely the opposite 中的it，为何指代的是radio，而不是距离更近的tool 或是private conversation？ 谢谢了

E选项没有看懂老师的解释

未发生，上一条字打错了...

这本书写在1165~1167之间，1165之后好理解，因为被发生的事肯定无法被记录。那么为什么记录了爹没死就可以说是写在1167之前呢？这里的假设一定是，如果爹死了，那么一定会写出来。
C选项，这本书在写著的当时，准确的记录了S的家庭结构。那么，爹如果在这本书写的时候已经死了，那这本书就会写出来。当然我们通过原文知道，这本书里面爹没死，那这本书就是在1167年之前写出来的了。

嗯 用图形背景原则解释看来是再合适不过了

这道题不太懂，求解释

这句话作为第一句话的平行evidence，都是用来表现贸易已经存在很久了的。

观察period的目的是为了后面的deduce the restraining force

for classifying，ing状态没有to do 状态改变的那么剧烈

BD，forcing前面没有和它平行的排除，
C ，may + possibly很明显的语义重复
E， as well as错了，ground-based和space-based是同级的概念，要用and；时间点事last year，时态用has done不对！

有没有人觉得这套题很难

代词指代的单复数啊！！！

必须严格的在格式上平行。Not only..but also的also是可以省略的。

note that you can't read this as "less (carbon dioxide ... and other gases...)", either -- i.e., with "less" applying to both things -- because "less other gases" doesn't make sense.
you could have "fewer gases" (= not as many different kinds), or "less OF the gases" (= a smaller total quantity)... but not "less gases".

the most straightforward thing in choice D:
"far less carbon dioxide and other gases that have..." appears to indicate that the engines emit other gases (not LESS OF those other gases).

虽然，形式上with状语表原因，不需要逻辑主语，但事实上，要和主句主语要形成因果关系，所以，逻辑主语事实还是存在的。比如本题，由于没有捕食者和非捕猎区的扩大，所以受影响的就是鹿的数量的增长，主语必须是鹿的数量，而不是官方统计。

D/E For consumers and businesses...Government predicts...意思是“为了consuers...政府才predicts. "the prediction is "for" them - and may not even mean that their rates will fall! " B选项被动语态不简洁： "the passive voice is indeed a problem, because it's unnecessary. And there's also an unacceptably long distance between the passive-voice action (will be greatly reduced) and the agent of that action (by the ...). "

E is too wordy. "appeared immune" is just fine on its own. Notice that we have "it appeared immune." The "it" here refers to the ozone. Thus, to say: "it appeared that it was immune" would be unnecessary.