American beer, with very few exceptions, varies from the mediocre（普通的）to the terrible. There are not many types of beer in the US—"light" and "dark" are two terms commonly used.
It is therefore normal to order beer simply by brand name. In a restaurant, in fact, it is quite all right to order "a beer", and they will tell you what they have.
It is not necessary, either, to specify quantity when ordering beer. If it comes in bottles or cans, you will get a bottle or can, and if it's "on tap"（可以随时取用的） you will get a glass, unless you order a "pitcher"（有嘴和柄的大酒罐 i.e.a jug）. The latter is very convenient thing to do, since you can then take the jug and glasses to your table and keep filling up without going back to the bar. （It is harder, however, to know how much you have drunk.）
Some beer comes in bottles with tops that look as if they need an opener, but you can, in fact, screw（拧开） them off by hand—though you have to be very careful not to hurt yourself. It is possible, in some stores and bars, to find a wide selection of beer from all over the world, especially Western Europe and Australia, and it is good fun to experiment with these.
Cocktails and "mixed drinks" are much more popular and rather stronger in the USA than in Europe, and visitors may not be familiar with some of the terminology（术语）. "On the rocks", as you probably know, means with ice, while "straight up" or "up" means neat and without ice.
There are hundreds of different cocktails, and there is no space here to list all the different names.
The Hard Stuff
In America "whiskey" means bourbon（一种烈性威士忌酒，最初为美国肯塔基州Bourbon地区所产） unless otherwise indicated. Bourbon is a rather oily spirit made from maize（玉米）. Rye（黑麦威士忌酒） whiskey is called "rye" and Scotch whiskey "Scotch".
In bars wine can often be bought by the glass. Don't be misled by names such as "Chablis" is used to refer to white wine, and "Burgundy" to red—Americans seem never to have heard of white Burgundy.