[ Tenses ]
They __________ this research for years.
A. have done
B. have been doing
C. were doing

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IF CLAUSE › ViewIf you get back late, I………………. angry.
A. be
B. will be
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D. is
Tenses › View
What is the structure of the present continuous tense?
A. Subject + will be + verb-ing
B. Subject + have/has + verb-ed
C. Subject + was/were + verb-ing
D. Subject + am/is/are + verb-ing