He must have had an accident,or he then.A.would have been hereB.had to be hereC.should be hereD.would be here请老师详细讲解这道题，为什么选A项而不能选其他项啊？这个题中then的作用是什么啊？then的用法有哪些啊？谢谢老师啦。
I saw a film. 与 I have seen a film. I didn't see a film. 与 I haven't seen a film.I was a good boy.与 I have been a good boy.I wasn't a good boy.与 I haven't been a good boy.它们到底是什么意思？区别的本质在哪？
He says he is tired.
He said he was tired.
He said he had been tired.
请问老师这三句话怎么理解？我完全不明白第 1 句和第 2 句。他说自己累，这个说的状态一旦形成不就是过去了吗？不过去就没有说啊~! 怎么会有says呢？
我好像陷入...
句子：Former Colorado governor Richard Lamm hasbeen quoted as saying that the old and infirm "have a duty to die and get out of the way," so that younger, healthier people can realize their potential.翻译：用前科罗拉多州州长xxx的话来说，年老体弱者“有责任死...
...ption of the education system in the United States , no (other) system hasbeen studied more intensely than the one in japan . 这是一道改错题，原题是没有other，参考答案是要加other,但我感觉不加other语义也是通顺的，想问下各位老师为什么这里一定要加ot...
...help me improve the grammar in this short
essayIn some countries there hasbeen an increase in the
number of parents who educate their children themselves at home instead of
sending them to school.Do you think the advantage of this outweigh the
disadvantages?It is a rising trend that numerous of par...
...he only apparently significant difference in the Americas 11,000 years ago was the presence of human hunters of these large mammals. Was this coincidence or cause-and-effect?请问老师，这里的see是什么用法？是指某件事情被看见发生了吗？ 字典上貌似没有找到相关释...
But
Tiare Johnson would never under any circumstances have been rich. She could not
keep money. The daughter of a native and an English sea-captain settled in
Tahiti, when I knew her she was a woman of fifty, who looked older, and of
enormous proportions. Tall and extremely stout, she would have bee...
...in his life. ） 4.It was the greatest regret in his life that he had been absent from the graduation ceremony.5.It was the greatest regret in his life that he had not attended the graduation ceremony. 请教老师，句子1,2,3 的主语有何差别？句2中含有不定式的名词短语...
老师好，下面句子里，Huge progress hasbeen made against these diseases since an agreement in 2012 by pharmaceutical firms to donate billions of dollars’ worth of drugs. “billions of dollars’ worth of drugs”为什么要加worth of？直接说 billions of dollars’ drugs不行么？...
Schools remain very much what it has always been, and what changes have occurred cannot be attributed to technology.老师好，请问主语从句what changes have occurred 中what充当什么成分？
... and Tianjin are more closely connected and the urban environment has also been greatly improved."Fifteen years ago这个时间的立足点是从现在算起，正常下其后应该用一般过去时劳烦专家老师为我解惑，最好有个时间轴，具体，我的理解能力确实差点儿...
...ention of other teams, who had sent their own leaders, to meet with her as was the custom. 1、曹老师之前提过第一个句子as引导比较从句，第二句是否也是比较从句？2、为什么第二句的was在the custom之前呢？3、加不加逗号对于句子有什么影响？谢...
原句：We asked some friends around to watch a film, but the video was playing up and it eventually broke down.翻译：问题一：ask around的本意不是询问的意思吗？问题二：还有was playing up不应该是had been played up吗？表示电影已经开始了