请问这是个什么句子 and hence后为什么主谓都省略了? and hence中的and和谁是并列关系？ Under modern conditions,this
requires varying measures of centralized control and hence the help of
specialized scientists such as economists and operational research experts.
...照应”，这个问题里，前面用的单数work
visa，但后面却用they来指代。我在一份听力文件中又看到了这样一句话，是与之相反的情况，不确定能否也用“语境照应”来解释这种情况：That’s
why I love going to musicals because it’s the perfe...
不定式可以做定语，例如：The boy to write this letter needs a pen. (to write this letter 为定语，修饰名词boy) /写这封信的男孩需要一支钢笔。There is nothing to do today.（to do为定语，修饰名词nothing）/今天没有事要做。请教一下老师，什么情...
Though ostensibly a book about creativity, the author frequently veers off to discuss animal emotion and intelligence.麻烦请问亲爱的老师，though后可以只加个名词吗？是不是应该加个句子？
...ks carefully, who observes with curiosity, and who seeks to connect with the place he/she visits, with its history, its flavors, and its people.connect后紧跟一个with，这是什么用法？后面还有个with。
...度时，通常用一般现在时代替现在完成时。如：It’s a long time since I met you last. 从上次见到你，已有很长时间了。It’s a fortnight since I last saw her. 我有两个星期没有看见她了。我的疑问1:这两句主句为什么可以用一般现在时?其条...
...or man
when he died.为何不能说＝He died when he was a poor man呢
c.The fire is burning low这一组夸克说省略后续成分不影响句意。是在说low是状语吗？第2组The weather is
continuing mild.这一组，需要和补足语（complementation）连用。所以这个地方，mi...
...思应该是“感到寂寞的”，如：Without friends, he felt lonely in a new city. 在一个新的城市里，他没有朋友，感到孤独。但是它可表示“令人寂寞的”吗？比如，可以这样说吗？It was a bit lonely being an only child. 独生子女有点寂寞。这个...
People who work in offices are frequently referred to as “white-collar workers” .这里的 be referred to as，其中的 refer 是不及物动词吧，所以才接介词 to；可是不及物动词不是没有被动式吗？以及后面的 as 又做什么成分?
She used to wait outside film studios all day, just _____ (appear) in crowd scenes.老师，这边填to appear, 是目的状语吗？ 但是为什么不可以认为是结果状语，用appeared, 站了一整天，也仅仅只是出现在群演的画面中。