[ Tenses ]
The theory of relativity ____ a major breakthrough in 1905.
A. was
B. is
C. will be
D. being

Random Topics:
Present Simple/AffirmativeVerb Patterns / IngContrastive ConjunctionsRelative - ConditionalAbstract NounsNarrative TensesCardiology ServicesPrepositions and TensesProgressive TensesContrast Linking WordsOther quiz:
Conditional Sentences › ViewShe didn’t do the test because it was too difficult.
A . If the test had been too difficult, she could have done it.
B . If the test hadn’t been too difficult, she could have done it.
C . If the test were not too difficult, she could do it.
D . If the test hadn’t been too difficult, she couldn’t have done it.
Vocabulary and Grammar › View
Which word means “to hurt”?
A. leave
B. harm
C. selfish
D. difficult