Question

_____the beginning of the 19^th century did scientists know that all matter is made up of atoms.
A,At     B,By     C,Up to     D,Not until

Answer 1

D

试题分析：句子用了部分倒装，所以前面用Not until
点评：句首状语为否定词或半否定词的句子。这类词或短语主要有never, neither, nor, little, seldom(很少，不常）, rarely（很少，罕有）, hardly, scarcely（几乎不，简直没有）, no sooner（立即）, not only, in no way（决不）, at no time, few, not, no等, 用部分倒装。部分倒装是把be动词、情态动词、助动词放到主语之前。如果句子中没有这些词,要在主语之前加助动词do / does / did等,而把原来的谓语动词变成原形放在主语之后。