ron关于og 12 125中助动词的用法（已解决） - ChaseDream

umm，算是manhattan说的不太好的一个地方，贴上RON在论坛上的补充quote：

关于helping verb的更详细解释（RON）：
1 * if you have than/as + subject + FORM OF "TO BE" as the second half of a comparison, then you must have another form of "to be" in the first half of the comparison.

2 * if you have than/as + subject + HELPING VERB as the second half of a comparison, then you must have the SAME helping verb (perhaps in a different tense) in the first half of the comparison.

3 * if you have than/as + subject + FORM OF "TO DO" as the second half of a comparison, then you must have an ACTION VERB (or another form of "to do") in the first half of the comparison.

here are some examples:
#1
If current trends continue, by the year 2010 carbon emissions in the United States will soar to a level more than one-third higher than that in 1990, according to official projections.

also

parking spots are disappearing much more quickly today than they were yesterday.
#2
james can negotiate with salespeople more effectively than stephanie can.
i can run much faster than i could before my most recent knee operation. (note that "could" is the past tense of "can", so these are the same helping verb.)
#3
parking spots disappeared much faster today than they did yesterday.
tanya eats more slowly than she did when she was a teenager. (note that "did" doesn't have to have the same tense as the action verb)

个人的理解：

example #3：很confusing的一点，这里不同的时态eats 和did（这个did竟然不是用ate；而这一点在manhattan的章节中清楚说明是要用the working verb，在不同的tense时态中）

所以呢：和大叔yavev6的讨论，大叔的理论就是manhattan上面的那个例子都是并列句，而这里这个例子是比较句

至于为什么有这种情况？

并列句也就是所谓的two independent clause，而比较句是一个independent clause里面内置的比较结构

一个是两个句子，一个是一个句子；所以，可能是为了清晰或者unambiguous，第一个的helping verb的补出在

时态不一致的情况下，是要补出 exact working verb

open to discussion

-- by 会员 DUKB24 (2013/1/3 22:45:03)

后来我又翻了曼哈顿比较章节，发现5th中130页有写在害怕引起歧义时可以用助动词代替。

-- by 会员 starlitcream (2013/1/4 10:19:26)

?Tanya eats more slowly than ~~she~~ ~~did~~ when she was a teenager.

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以上摘自于我当时的笔记，现在有点忘了，好像是这样如果在比较句中是两个不同时态的实意动词再做比较，后面出现的实意动词可以用其时间状语限制下的助动词来替代前面的实意动词。
?Tanya eats more slowly than she did when she was a teenager.
the same amount of acreage producestwice as many apples as it didin 1910.
由于完美平行，且不会引起歧义所以不用担心不知道did到底指的是那个动作，这也就是OG解释所说的：

?An action that occurred in 1910 requires a verb in the past tense. The two elements being compared must be grammatically parallel. The same amount … produces is paralleled by as it did (produce understood). The subjects amount and it are parallel, as are the verbs produces and did (produce).

天呐。。。。

-- by 会员 starlitcream (2013/1/4 15:49:47)

in general,
* if you use did/do/does/etc. to stand for an action verb, then it can be parallel to any tense of that action verb.
e.g., you can use "did" in parallel to saw (which is in the same tense), but you can also use it in parallel to has/have seen, will see, sees, etc.

so, for instance,
No one else will ever play that piece as well as you did last night.
--> this sentence is perfectly correct, as is the one about acreage in the OG.