Day 80. Cav =hollow (中空的）

Day80cav=hollow(中空的)* 拉丁文 cavus (= hollow)cave [kev ]n. 洞穴 v.(使)凹陷 cavern ['kavan ]n. 巨穴;大洞cavernous ['kavones ] adj. 如洞穴的;多洞穴的;凹陷的 cavity ['kaveti ]n. 穴;洞;凹处;腔concave [ kan'kev ]ad凹的;凹面的con- = together」convex(凸面的)e excavate [ekska.vet]v.挖空 ，挖出ex-= outex+cav+ate=out + hollow+ v.excavation [.ekske'vefen]n 挖掘;发掘 excavator ['ekska.veta]n.挖掘者;挖土机