[ Perfect Tenses ]
My back hurts because I … here for three hours.
A. was standing
B. have stood
C. have been standing
D. had been standing

Random Topics:
Relative Clauses and etcPersonal PronounQuantifies and Modals of DeductionSimple PastVerb, Object, PrepositionSports VocabularyModal Verbs and Gender NounsGrammar Past and Future TenseGerundSuperlative AdjectivesOther quiz:
Conjunctions › ViewChoose the conjunction in this sentence: “We stayed home because it was raining.”
A. home
B. stayed
C. because
D. raining
Articles & Quantifiers › View
You look tired. Are you doing ______ work?
A. many
B. much
C. few
D. plenty
Grammar › ViewIdentify the adjective in the sentence:
The ball is so big.
A. ball
B. is
C. big
Plural › View
What’s the plural of wolf?
A. Wolfs
B. Wolfes
C. Wolves