221. economize on (=save sth. instead of being wasteful) 节省

220. put sb. at his / her ease (=free sb. from worry or nervousness)使某人感到无拘束

219. at (one’s) ease ( = without worry or nervousness) 自在,不拘束

218. with ease ( = easily) 容易, 不费力

217. on earth 究竟, 到底, 全然

216. a word in one’s ear 私房话, 秘密话

215. have an ear for (=have keen recognition of sounds esp. in music and language)对..有鉴赏力

214. by ear (=play music from memory without having seen it printed) 凭记忆,不看乐谱

213. be eager for 想得到, 盼望

212. be in duty bound to (do) (=be required by one’s job or esp. by conscience) 有义务(做)