[ Grammar ]
The tetracyclines, _____ antibiotics, are used to treat infections.
A. are a family of
B. being a family
C. a family of
D. their family is

Random Topics:
Comparatives - SuperlativesVerbs & Verb TensesTransitive and Intransitive VerbVerb to bePrepositions and ConjunctionsAnalogyAdverb of Frequency and TensesVerb Present Simple TensePossessive PronounsPresent Progressive (Future)Other quiz:
Present Simple and Present Continuous › ViewShe ……………………goes to school by motorbike.
A. often
B. am
C. is
D. are
Prepositions › View
Minh Duc went _________ a walk.
A. to
B. at
C. for