[ Grammar ]
Acid rain can be caused due to combustion of fossil fuels or erupting volcanoes or rotting vegetation which ____ sulfur dioxide and nitrogen oxides into the atmosphere.
A. release
B. releases
C. is releasing
D. have released

Random Topics:
Past Perfect and Past Perfect Continuous TenseAdverbs of Manner, Likes and PreferencesModals and PhrasesGrammar - First ConditionalTime and CalendarPassive Voice - Present Simple and Past SimpleTo Infinitive/Bare Infinitive/GerundsApologizingClauses of ReasonRelative Pronouns with PrepositionsOther quiz:
Comparatives or Superlatives › ViewThe cactus is one of the____plants in the world
A. dangerousest
B. most dangerous
C. more dangerous
D. dangerous
Grammar › View
Identify all the nouns in the sentence.
The puppy barked at the boys.
A. puppy
B. boys
C. barked
D. puppy, boys
Can vs be able to › ViewMary __________ sing. She’s part of the school band.
A. is able to
B. was able to
C. can
Grammar & Vocabulary › View
Choose the Correct Sentence
A. Listen! The birds sing outside.
B. Listen! The birds are singing outside.
