"Soybeans," said the governor of Arkansas.

"Wheat," said the governor of Montana.

"Coal," said the governor of Utah.

Last night at the Chinese Embassy, it was kind of like that little moment in the movie "The Graduate." You remember, the time when one of Dad's business buddies leaned over the perplexed, fresh-from-college kid and whispered knowingly, "Plastics."

This time it was maybe two dozen governors, and nobody was whispering at a dinner hosted for them by Chinese Ambassador Chai Zemin. The occasion was officially a function of a three-day National Governors' Association meeting here, and unofficially a wonderful chance to lubricate plans for more trade missions between China and the United States.

At last count, some 20 governors plus wives and entourages had visited the People's Republic. The idea is to see the Great Wall and sell to the Chinese, in these days of normalized relations, whatever an American state has to offer.

"Minerals," said the governor of Nevada.

"Reynolds Meta," said the governor of Virginia.

"Do you have a card that I could take?" said John Carlin, the governor of Kansas, to Hu Nansheng, second secretary of the embassy. "Very good, very good. I'll check with my staff when I return to Kansas that things are going properly."

But before things got too boring, especially at a reception where only orange drink, Coke and American beer was served ("We have very strong liquor at dinner. You'll see," explained Yu Zhizhong, a first secretary at the embassy), dinner was, in fact served.

To the Americans, it was exotic. And delicious, In order: fried shrimp, fried duck, Chinese yellow fish, steamed duck, soybean curd, pork dumplings, a rice dessert. And lots of wine and mao tai, the Chinese liquor which was as strong as the first secretary promised.

The bottom line was that it gave the governors something to do besides attend meetings with titles like "Review of federal fiscal and management issues: FY 1981 budget, general revenue sharing. Grant and Cooperative Agreement Act . . ." (and it even goes on for some length after this.)

More than a few governors agreed off the record that the conference had some moments that were pretty godawful dull, but all acknowledged it as a good chance to hash out common problems. So in between the soybean cord that burned everybody's tongue, Richard Thornburgh of Pennsylvania, Bruce Babbitt of Arizona and Bill Clinton of Arkansas talked nuclear power plants.

Thoroburgh, by the way, is leaving for China on Sunday. "I'm going to put aside my budget problems and Three Mile Island," he told Babbitt. "I'm ready to hit the deck."