rare/rarely

rare /rɛə/ adj. 1. 稀有的，难得的：a rare metal 稀有金属；on rare occasions 难得，不常 It is rare for him to come late. 他很少迟到。 2.稀薄的，稀疏的：the rare air of the mountains 山上稀薄的空气 (［反］dense)

 rarely /ˈrɛəli/ adv. 很少，难得：He is rarely ill. 他很少生病。I rarely meet him. 我难得碰见他。Rarely do we see them nowadays. 近来我们很少看见他们。［考句］ San Francisco is usually cool in the summer, but Los Angeles rarely is.旧金山夏天通常凉爽，而洛杉矶的夏天很少有凉爽的时候。