※ 引述《tucson (tucson)》之铭言：
: 补述用法的that前面出现逗号(在经济学人)
: http://www.economist.com/node/21689514/print
: These suck the propellant up by capillary action, obviating
: the need for pumps. The propellant itself is
: a substance known as an ionic liquid, that consists of positive
: and negative ions which can be separated by passing a current
: through the liquid and then, because they are electrically
: charged, accelerated by an electric field. (Both current and field
: are supplied by a battery on board the satellite.)
: 看来 补述用法/限定用法 中that 加上逗号 越来越被接受了
: 说that不可以用在补述用法/非限定用法的人
: 是不是觉得比经济学人的编辑更懂英文呢?
Huddleston and Pullum (The Cambridge Grammar of Modern English, 2002. p1052)
say that "who" and "which" are normally used in non-restrictive clause, but
add that some speakers do accept "that."
I use "who" and "which," but accept "that."

我看到会觉得很怪 怪到不确定对不对 所以都叫学生改掉XD

事实上这里(句)用that不奇怪, 而且是最佳解(比起用which)作为关代的that在使用上确有一些限制, 并有其原理, 但很可惜大多流于教条式背诵这句用that比用which好的其中一个原因是下文出现which,前用that可避免连用两次which并且以这句情况, 采, that的限缩范围能较, which 小/精准

我没看完全文 但是我的话可能会调换 看来我就是无法接受的那一派XD

像原句这种情况采that的频率, 通常比which高 (原因是另个故事了)其实只要回答此句,that 是指代 substance 或 ionic liqid大概就知道对此句的理解差异了这里如果用which, 就像我上文说的, 又多开了一个代指前文整句的可能性(而这种可能性在为求精准写作时宜避免)因此此句先出现that 才出现which 是最合理且精确的写法

我怎么看都一样阿... 两个都指substance(know as...) 确实有可能指liquid但是我觉得这不是文法可以判断的 一般来说这种是语义文意去判断 如果要讲清楚我可能会放两个逗号或者整句改写避免误解 因为放逗号就变补述了 我仔细想想这边文意上来说不会指液体？ 虽然有可能指的是iconic liquid 但这就是那个substance啊 cuz it’s known asiconic liquid?