Hi Jing Jing. He smokes fewer than 10 cigarettes and drinks less than 5 beer a day. You can count cigarettes and bottles of beer, therefore you use fewer, rather than less. As for beer, you can say I drink beer or if you are referring to a number of drinks, you would say 'bottles of beer'. I think it's kind of like "wo xihuan he pijui, or wo meitian he wu ping pijiu" (please correct me if I have made mistakes here). You use 'less' with non count nouns; examples include money, time, etc. "I have less time these days because I am studying so hard". Just ask me if you don't understand the above comments. I would be happy to practice mandarin with you, by the way.