[ Grammar ]
____ the problem sum many times to his student, Mr Tay gave out a sigh of frustration.
A. Have explained
B. Having explained
C. Have had explained
D. Have been explaining

Random Topics:
ClausesTenses and Verb FormsGrammar (want to/ need to/ have to)Modal "Have to"ConditionalsImperative SentencesAdjectives and PrepositionsNoun PhrasePassive Voice Active VoiceModal SpeculationOther quiz:
Homophone & Homonym › View The bride wanted china for her table.
A. dinnerware
B. a nation
Grammar › View
He __________ to the library every week to study.
A. go
B. goes
C. gone
English Morphosyntax › ViewAlex leaves the house after the kids ___________ to school.
A. go
B. gone
C. went
D. didn’t go
Homophones › View
The words “course” and “curse” are homophones.
A. True
B. False
