2018考博英语必会语法知识点：倒装句之部分倒装
2018考博英语复习初期，夯实基础是首要任务，作为英语最基础的知识就是语法，新东方在线考博英语频道整理了一系列考博英语必会语法知识点供考生们参考复习。
倒装句之部分倒装
当否定词语置于句首以表示强调时，其句中的主谓须用倒装结构。 这些否定词包括no, little, hardly, seldom, never, not only, not until等。本题的正常语序是 Smoking is permitted in the meeting-room at no time.
2) Not until the early years of the 19th century ___ what heat is.
A. man did know B. man know C. didn't man know D. did man know
答案D. 看到Not until…的句型，我们知道为一倒装句，答案在C，D 中选一个。
改写为正常语序为，Man did not know what heat is until the early years of the 19th. 现在将not提前，后面就不能再用否定了,否则意思就变了。