Two years later, her brother disappeared in the war, never ________ again.
Come and see me whenever________________.
The system has been designed to give students quick and easy_______ to the digital resources of the library.
Either you or one of your students _________ to attend the meeting that is due tomorrow.
___________ certain that his invertion will lead to the development of production.
He is brave, hard-working and kind, so he was elected ________ monitor of our class.