It takes more than a week to become an Old China Hand. But in just a few days -- by asking questions and poking around -- one can put together a primer for travel to China in general and this city in particular.

Here are some basic questions and answers:

Q. Is the water safe to drink?

A. Repeat after me: "I will not drink the water raw." Hotels serve water that purportedly is boiled; it is delivered to your room in carafes. To be perfectly safe, you'd be wise to bring water purifying chemicals available back home from druggists or stores selling camping gear. You could, of course, drink the Chinese beer.

Q. Is the beer good?

A. Not bad. Also, the price is terribly right. At a hotel bar, beer costs 50 cents for three-quaters of a liter. Beer and orange soda are offered at all meals except breakfast.

Q. Are all bar prices so low?

A. They're lower than you might expect. In the same hotel bar, a shot of Chivas Regal is $1.80. The same price will get you real cognac from France. Gin is $1.20, rum 90 cents and maotai (a bitey local liquor) is 80 cents.

Q. What's the greatest thing about a trip to China?

A. The people, no doubt about it. You come face to face with them everywhere, even at such tourist attractions as the Forbidden City and the Great Wall. Wherever you meet them, they'll exchange greetings ("knee-how" is good anytime), and they'll smile at you and wonder about you.

Q. How's the foods?

A. Great -- if you like Chinese food, and many Americans do. A variety of dishes are served at each meal and you may have as little or as much as you want. The dishes are heavy on vegetables and short on meat. Don't expect steaks, chops and so forth.

Q. Is all the food served Chinese cuisine?

A. No, not always. Hotels realize that you might not like a Chinese breakfast of rice gruel and other soupy things and so offer fried eggs, omelets and toast.

Q. Is only tea served?

A. It's always offered, but coffee (not usually served in China) is available in tourist hotels. The coffee we've encountered was somewhere between all right and good.

Q. Is there room service?

A. Sometimes yes and sometimes no, when it comes to food. The room attendants are usually men, not maids, and they'll bring you a thermos of hot water at any time for instant coffee (bring your own) or tea. Fragrant jasmine tea often is served.

Q. Must you use chopsticks?

A. Many tourists wobble through a meal with sticks. But most places will produce forks, if asked.

Q. Should you use chopsticks?

A. The greater wisdom is to ask for a fork. Henry Herr Gill, director of photography for the Chicago Sun-Times and a frequent visitor to China and other places in the East, is convinced woden chopsticks cannot be made clean by an ordinary washing. Nobody seemed upset when I produced plastic knives and forks brought from home.

Q. Can you get snacks?

A. There are many shops on the streets of Peking where you can get soft drinks, crackers, cookies and other nibbling items. I saw none that looked appealing. The Peking Hotel bar had sandwiches, ice cream, cakes, apple pie. Prices are quite reasonable, except that Coca-Cola is 90 cents a can.

Q. Didn't you find any food you liked?

A. Oh, yes, indeed. Peking duck is, as billed, a super dish. These ducks are force-fed, slaughtered, plucked and cleaned and slathered with honey for two days before being baked. The meat is cut into small bits, touched lightly with plum sause, topped with slivers of leek and rolled in a crepe. As for other Chinese dishes, we saw many tourists who ate them with great delight.

Q. How does one get to China?

A. Tourists generally get here on a tour package. There are many available, as any travel agent will tell you, and because of the distance, the demand and China's need for foreign exchange, they are not cheap. I was a guest of Pan yamerican World Airways, which recently inauguarated China service from New York and the West Coast by way of Tokyo, and of Lotus Tours.

Q. Is it a long trip?

A. Whew, it's a beauty. From my front door in a Chicago suburb to Peking took 25 hours and 25 minutes. On the 7,045-mile (non-stop!) hop from New York to Tokyo, Pan Am served two dinners and showed two movies.

Q. How many American tourists go to China each year.

Not counting businessmen and others who managed to get visas without buying a tour, there were 40,000 American tourists last year, according to the China International Travel Service. A slight increase is expected for 1981.

Q. Is it difficult to visit the Great Wall of China?

A. It's easier than a visit to the Grand Canyon. About 30 miles out of Peking by bus or train, you come to a section of the wall that's a popular place for visiting. It's also a touristy sort of place with a restaurant, a parking lot for tour buses and souvenir stands, including one named for Marco Polo. But the Great Wall is a super destination for visitors, including the Chinese.