Energy, passion and a burning desire are, you see, ________ true learning takes.

The two boys look so much alike _______no one can tell them apart.

 —How long has John been here? — Two years, _______ he still has no friends.

______ is expected, according to the online survey, is _______ prices of houses will not go up an more.

It was not long _____ he was born that his mother died of illness.