[ Adverb and Noun Clauses ]
When ………………. is not known.
A. was the wheel invented
B. the invention of the wheel
C. inventing the wheel
D. the wheel was invented
Random Topics:
GerundPast Simple - Present PerfectAuxiliary WordsWh- Questions Present Simple TenseHow many / How much - Is there / Are thereVerb TensesConjunctions and Sequence ConnectorsAdverbs, Modals, Preposition of timeVocabulary and PrepositionsPresent/Future/Past Simple/Present PerfectOther quiz:
Grammar › ViewWhich of the following matches the definition correctly? It may be a statement, a question, or a command.
A. statement
B. question
C. command
D. exclamation
Grammar › View
Please ring me up as soon as he ____________ (arrive)
A. arriving
B. arrived
C. arrive
D. arrives