[ FOR & SINCE ]
Sue has only been waiting _______ 20 minutes.
A. since
B. for

Random Topics:
ConjunctionsThere is or There areVerbal CommunicationParallelism and Subject Verb AgreementPresent PerfectPronouns and AntecedentsPast Perfect & Past SimplePresent Perfect and Present Perfect Progressive TensesAdjectives & PrepositionPresent simple & ContinuousOther quiz:
Tenses › ViewA clean surrounding ____________ a healthy living.
A. ensured
B. ensures
C. will ensure
Relative Clauses and Usage › View
This is the artist ______ painting won the award last year.
A. whose
B. whom
C. which
D. who
Grammar › ViewJan had green eyes, but you never saw them.
A. simple
B. compound
Grammar - TOEIC › View
She is not storng enough __ to work yet.
A. to go
B. go
C. going