Bob ......................... swimming in Jeddah last month.

His breathing problems… .............. by smoking.

I got a really good idea for an essay while I .................. the course book last night.

Which one of the underlined words or phrases is INCORRECT? Collecting insects and worms were the most difficult part of …

Dairy products should… ............... to keep them fresh.

If I have extra pens, I always ....................... them to other students.