By the time the teacher entered, the students ___ down.
A. have sat
B. has sat
C. had sat
D. sitting

Random Topics:
Adjective & AdverbsIntermediate PrepositionsAuxiliary VerbsGrammar Comma UsagePersonal PronounModals Of SpeculationAdverbs of TimeConditionals and Modals of ProbabilityFigurative LanguageModal and Phrasal VerbsOther quiz:
Grammar › ViewPeter’s flat is hot. He wishes ___.
A. that it were not
B. if it was not
C. it had not been
D. if it would not
Vocabulary › View
Due to human impacts, the rate of climate change is now thought to be too great and seriously threatens ______
A. Century
B. Invasive
C. Erosion
D. Biodiversity
Subject – Predicate › ViewWhich sentence contains a compound subject?
A. Living inside the old barn were a large brown horse and a short white cow.
B. Only two dozen children rode the bus that day, but it was still very noisy.
C. The green cicada is an insenct found in yards and parks all over town.
D. A small lizard slithered his way under the rock and out of sight.
Gerund vs. Infinitive › View
Is crying a participle?
A. Yes
B. No
C. Depends on the context.
