We hung a net round the bed, which could protect us _____ mosquitoes and other insects. 

_____ the coach was twisting and turning _______ the bumpy country road, the travelers felt that they were pulling themselves apart.

Did you benefit _________ the new way of doing business?

High-speed trains which travel through my home town ______ up to 250 km per hour make it a small world. 

I was so tired that __ I closed my eyes, 1 fell asleep．