The method for making beer has changed over time. Hops （啤酒花）, for example, which give many a modern beer its bitter flavor, are a __26__ recent addition to the beverage. This was first mentioned in reference to brewing in the ninth century. Now, researchers have found a __27__ ingredient in residue （残留物）from 5000-year-old beer brewing equipment. While digging two pits at a site in the central plains of China, scientists discovered fragments from pots and vessels. The different shapes of the containers __28__ they were used to brew, filter，and store beer. They may be ancient "beer-making tools," and the earliest __29__ evidence of beer brewing in China, the researchers reported in the Proceedings of the National Academy of Sciences. To __30__ that theory, the team examined the yellowish, dried __31__ inside the vessels. The majority of the grains, about 80%, were from cereal crops like barley （大麦）, and about 10% were bits of roots, __32__ lily, which would have made the beer sweeter, the scientists say. Barley was an unexpected find; the crop was domesticated in Western Eurasia and didn’t become a __33__ food in central China until about 2,000 years ago, according to the researchers. Based on that timing, they indicate barley may have __34__ in the region not as food, but as __35__ material for beer brewing. A) arrived B) consuming C) direct D) exclusively E) including F) inform G) raw H) reached I) relatively J) remains K) resources L) staple M) suggest N) surprising O) test