I’ll never forget the pleasant days ____ I spent with you.
Every possible means ___ to prevent the air pollution, but the sky is still not clear.
A friend of ______ went to the railway station to see ______.
Do you know when Mr Brown_______ ? When he_______ , please let me know.
_____ get a better score, she has been studying hard all day.
He said that his bike _____ stolen and he _____ telephone the police.