——You don’t go to that cinema quite often, do you? —— No, I only go there ______ because it’s too far away from my house.

He began to take political science        only when he left school.

As is known to all language learners, the newly learnt words will soon be forgotten unless ______ used in everyday communication.

Susan advised me not to buy the vase, but I bought it _____.

A model or an experiment in a science class can help us see things which would_______ remain hidden.