The more-or-less rhythmic succession of economic booms and busts (is / are) referred to as the business cycle.
A. is
B. are

Random Topics:
Grammar and VocabularyConditionals (0 - 1 - 2)Countable & Uncountable NounsDemonstrative PronounsPast and Future TensesComparative and Superlative AdjectivesModal Verbs for Permission and ObligationGrammar - Present Perfect TenseGrammar - Wh QuestionsHomophonesOther quiz:
Future Tenses › ViewJohn and Sam ______(meet) at Starbucks on Monday at 5.00.
A. John and Sam will meet
B. John and Sam are going to meet
C. John and Sam are meeting
Adjective › View
All the girls fell in love with the ________ teacher.
a.handsome new American
b.American new handsome
c.new handsome American
Are the teachers in the meeting?
A. Do you know if the teachers are in a meeting?
B. Do you know if the teachers in the meeting?
C. Do you know if the teachers in a meeting are?
Tenses › View
Isn’t it strange that you ____ for Mark’s surprise party all week, but you ____ him a birthday present yet?
A. are preparing / didn’t buy
B. prepared / don’t buy
C. have prepared / aren’t buying
D. have been preparing / haven’t bought
