[ Tenses ]
They were watching television when suddenly someone ______ at the door.
A. knocks
B. have knocked
C. was knocking
D. knocked

Random Topics:
Relative Clauses and etcGerunds and ModalsPast Simple VS Used toSentences Function and StructureVerb Forms and PrepositionsTenses and Figurative LanguagePre-intermediatePresent Simple and Present ContinuousAdverbs and Time ExpressionsCommunicative GrammarOther quiz:
Grammar › ViewShe _____ be at home, I saw her in the cinema.
A. might
B. doesn’t have to
C. can’t
D. needn’t
Mixed General Quiz › View
The Great Barrier Reef is a popular tourist destination ___ Australia.
a. from
b. at
c. in