[ Grammar ]
Burning yard waste releases mold spores, soot, and other contaminants that can aggravate allergies and cause ____ problems.
A. respirator
B. respiration
C. respiratory
D. respired

Random Topics:
Clauses and GerundsSimple Future - WillModal AuxiliaryCorrelative ConjunctionAdjective ending with ED & INGAsking & Giving OpinionPast and Perfect TensesPresent, Past, and Future TimeZero ConditionalSimple Past ContinuosOther quiz:
Past Tenses › ViewHe has … finished his homework. He can go to the park now.
A. for
B. never
C. ever
D. just
Adverb › View
What are the adverbs in the following sentence?
Nixon stated firmly, “I am not a crook!”
A. Firmly + crook
B. Firmly + not
C. Stated + firmly
My mother and father ___________ to Australia.
A. have never been
B. has never been
C. has went
D. have went
Paired Conjunction › View
He is …….. intelligent, ……… very funny.
A. not only….but also
B. either……or
C. neither…..nor
D. both…..and