As is known to all language learners, newly learnt words will soon be forgotten unless ______ used in everyday communication.
Father insisted Tom _____ all his homework before he went to bed.
I met this guy _____ some other occasions but he did not seem to recognize me.
I don’t like the lecture yesterday. Most of what the speaker said was _____ the subject.
The demand for _____ skilled workers is still increasing.
My new neighbor is a _____ person; he never speaks to anyone and nobody knows where he is from and what he is doing.