He was busy writing a story, only ______ once in a while to smoke a cigarette.

It’s the ability to do the job _______ matters not where you come from or what you are.

Some people who don’t like to talk much are not necessarily shy；they ______ just be quiet people.

It is always difficult being in a foreign country, __________if you don’t speak the language.

He spoke about the country as if he had been there, but ________ he had never.