[ Infinitive and Gerund ]
It is quite difficult ____________ how they did that.
A. imagine
B. to imagine
C. imagining

Random Topics:
SuperlativesGerund NounBasic GrammarGerund vs InfinitiveEmployment VocabularyCoordinating and Subordinating ConjunctionsJobsConditional Sentences Type 0, 1 and 2Simple Past ContinuosAdjective OrderOther quiz:
Grammar › ViewA: I’m going to learn Spanish.
B: Great! Spanish …………. a beautiful language.
A. is
B. are
Phrasal Verb › View
The Covid-19 pandemic reminds us to respect doctors and nurses, who______ others in our society.
A. go on
B. call back
C. pick up
D. care for