The city at one time must have been prosperous, for it enjoyed a high level of civilization.想问下这句话中at one time 都可以放在句子的什么位置，可以放在been之后吗？还有must have been 是推测的用法吗，可以详细解释一下吗，谢谢~
...焦点成分。所以，下列几句不可接受。①* lt was
carefully that he operated on the patient.②* lt was
thoroughly that they cleaned the house.③* lt was
violently that we expressed our views.④* lt was
reluctantly that the enemy accepted defeat.这里有没有背后的逻辑原因？...
both 可用于否定句吗？neither、either 和 both 在下面句子等同吗？which one did you chose？ plan a or plan b？Neither of them was accepted.both of them was not accepted.(可以这么说嘛？)either of them was not accepted.i do not like both of the men.(可以这么说嘛？)i do ...
Jobs have changed our modern means of communication， as wellas_____(enable)electronic products to become part of our life.1.填enableing，把as well as 理解为介词，除...之外2.填enables，把as well as 理解为准并列连词请问各位老师，我的两种理解是否正确？另外...
...如下：For example, if everyone in the family gets up early, wife will have enough time to prepare the breakfast for the whole family, children will have enough time to catch the school bus, husband will never forget to change his dirty shirt. 谢谢老师！
...文章中看到一句(划线部分)：But because of his selective outrage,and his history of negtive comments about Amazon CEO Jeff Bezos and The Washington Post, the newspaper Bezos owns, Trump's lashing out now reads as conflicited at best and faith at worst.划线中 as confilicted at best a...
—Would you like to see the film?—Yes, ______.A. I'd like to.B. I'd like to see.C. I'd like to see the film.这是一个群友问的问题，我感觉 A、B、C 好像都行似的，A 是简短回答，C 是完全的回答，但 B 呢？我想问问老师算错吗？谢谢老师。
...成：An adaptive law is introduced to reduce the parameter uncertainty and a backstepping control is adopted to eliminate the external disturbance.这里我用and 来并列，感觉读起来不太舒服，有没有更好的方法。谢谢!