[ Vocabulary and Grammar ]
Astronomers haven’t _______ signs of life in space.
A. see
B. saw
C. seen
Select your answer:
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Past Continuous TensePassive and Active SentencesCountable & Noncountable NounsPresent Tense vs Present ContinuousDeterminers & QuantifiersMix-TensesGrammar - Imperatives and LetCountable and UncountableTypes of Sentence StructuresOther quiz:
Grammar › ViewMr. Johnson, _____ a man waiting for you downstairs.
A. it’s
B. there’s
C. there are
D. they’re
Grammar › View
Can you hear those people? What ………….. (they/talk) about?
A. do they talk
B. are they talking
C. do they talking