[ Tenses ]
They …… frustrated when the students did not engage with the new rewards system.
A. must be
B. must was
C. must have been
D. must had been

Random Topics:
Grammar ClausesIndefinite and Reflexive PronounsGrammar: Simple Past and Past ContinuousVerbs & Phrasal VerbsDependent ClausesFunctional Sentence TypesReported Speech and SubjunctiveWishesPerfect Tenses of VerbsVerb PatternsOther quiz:
Correlative Conjunction › ViewYou can either wear open-toe sandals … shoes to work at the office.
- or
- nor
Tenses › View
Mum … ill all week so she’s going to the doctor today.
A. was
B. is
C. has been
