吸管 (xī guǎn) is a tube used for drinking, like a plastic or paper straw. It is different from 草 (cǎo), which means 'grass' or 'straw' as a material (e.g., a straw hat). In specialized contexts, 吸管 can also refer to a pipette or snorkel, but the HSK 5 meaning is the drinking straw.