[ 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:
Prepositions of Time › ViewI usually do my homework _________ night.
A. at
B. on
C. in
Modal Auxiliary › View
You … put a warm coat, it’s pretty warm today.
A. mustn’t
B. hadn’t
C. don’t have to
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
