[ Grammar ]
Other radioactive elements ______ since: actinium (Debierne), radiothorium and mesothorium (Hahn), ionium (Boltwood), etc.
A. were discovered
B. are discovered
C. have been discovered
D. had been discovered
Select your answer:
Random Topics:
Articles & Compound NounsModal "Have to"Preposition and ConjunctionAdjective ending with ED & INGCommas and Subordinating ConjunctionsSubordinating and Coordinating Conjunctions-ed/-ing AdjectivesGerunds and ModalsSimple Present and Present Continuous TensesPast Perfect Simple & Past Perfect ContinuousOther quiz:
Grammar › ViewIdentify the part of speech of the underlined word.
We do driving right!
___
A. Noun
B. Pronoun
C. Verb
D. Adverb
E. Adjective
Can, Could, May, Might › View
I won’t buy that for Mum because she ____ like it.
A. might
B. might not