auxiliary verb; modal verb
verb reduplication, used to soften tone or indicate a short action (e.g. 试一试[shì yī shì] or 看看[kàn kan])
(linguistics) stative verb
modal verb (e.g. 肯[kěn], 能[néng], 会[huì], 要[yào], 该[gāi], 得[děi], 愿意[yuàn yì], 可以[kě yǐ], 可能[kě néng], 敢[gǎn], 应该[yīng gāi])