The United States is behaving like a teen-ager with a credit card: It is buying everything.

The stuff includes imported cars, candles, copper and glass; shoes, hats, belt buckles of brass; coffee, sugar and ground fish, too. "Colonial" chairs from Taiwan? America bought some, new.

"I can't think of one goods-producing industry in the United States that isn't facing import competition," said International Trade Commission member Alfred E. Eckes.

Imported cars, which now occupy about 18.6 percent of the U.S. auto market, have captured most of the American public's attention. But the deepest import penetration has been in the home entertainment industry -- radios, televisions and stereos -- where foreign competition in 1984 took 61 percent of the domestic market.

Capital goods, metal-cutting machine tools chief among them, are another example of heavy import penetration. Foreign machine-tool makers last year held 39 percent of the U.S. machine-tools market, compared with a 9 percent import share in 1972, according to Department of Commerce figures.

The import binge in 1984 left the United States with a record $123.3 billion trade deficit. U.S. trade officials say that record will be broken this year with a shortfall of $150 billion. The 1986 trade deficit could be larger still.

"The consequences of the deficit were clearly apparent" at the ITC last year, Chairwoman Paula Stern said in her agency's recently released 1984 annual report. "An almost constant stream of petitioners found their way to our doorstep. . . . Industries that previously faced little or no serious threats from foreign competition suddenly found themselves turning to the commission for relief," Stern said.

Protectionist activity in Congress also increased. It seems that almost every federal lawmaker now has a business in his or her district that is threatened by imports. The upshot is an estimated 300 bills, all aiming to curb foreign competition.

"There's this tremendous worry everywhere that our whole industrial base is sinking, going under water like the Titanic, because of imports. That is just nonsense. The foreigners are not the cause of all of the economic problems in the United States," said Doreen Brown, president of the Washington-based Consumers for World Trade.

American industry should complain less about imports and do more to improve its export prowess, Brown said. But many U.S. industrialists, often citing problems related to a strong U.S. dollar, contend that talking about increasing exports is a lot easier than doing it.

The question for individual consumers and companies alike is price. Why pay more for a Made-in-U.S.A. product when you can buy something of comparable or better quality, often at a lower cost, from a foreign manufacturer?

Indeed, many U.S. companies that complain about imports have increased their purchases from overseas. Chrysler Corp., the nation's third-largest auto maker, is a prime example. Chrysler Chairman Lee A. Iacocca fought for continued quotas on Japanese cars. But Chrysler last year bought nearly 100,000 of those cars from its Japanese partner, Mitsubishi Motors Corp., for distribution in the United States.

Likewise, when it comes to parts such as wiring harnesses -- the bundles of wires used in automotive electrical systems -- domestic auto makers tend to look to Mexico and Taiwan. Domestic wiring harness manufacturers, such as Montgomery, Ala.-based National Industries Inc., are put in a bind.

Wiring harness manufacturers in Mexico pay their workers about $1.50 an hour. Workers in Taiwan get even less. Non-union, highly automated National Industries pays its people about $6 an hour. Despite the Montgomery company's reputation for quality and efficiency, it literally has to work overtime to keep contracts coming in.

"A few industries will virtually disappear because of changes forced by new technology, shifts in consumer preferences, and rising foreign competition, especially from lower wage countries," said Lionel H. Olmer, former Department of Commerce undersecretary for international trade.

The U.S. and world economies are going through a necessary period of adjustment, Olmer said. New industries will develop. The "old" industries that survive and thrive will do so largely because they will be successful in changing their product mixes, gaining production efficiencies, and otherwise altering the way they do business, Olmer said.