[ Tenses ]
Environmental pollution ____ ever since people ____ to gather together in towns and cities.
A. has existed / are beginning
B. had existed / were beginning
C. exist / have begun
D. has existed / began
Random Topics:
Noun and PronounGrammar - Verb FormsGrammar Double Object VerbsModal VerbsModal ProbabilityModals and Active and Passive VoicePast Simple Negative & QuestionsNoun, Quantifiers and SuffixesVerb + InfinitiveSimple Present and Present ContinuosOther quiz:
Grammar › View“When will this exercise end?”
A. He asked when that exercise would end.
B. He asked when this exercise will end.
C. He asked if this exercise would end.
D. He asked if this exercise will end.
Grammar › View
What are curtains usually made ___?
A. with
B. in
C. of