Question

【题目】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

Answer 1

【答案】D

【解析】看到Not until的句型，我们知道为倒装句。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，故选D。