211.be on duty 值班，值日，在上班时
212.be in duty bound to (do) (=be required by one‘s job or esp. by conscience) 有义务(做)
213.be eager for 想得到，盼望
214.by ear (=play music from memory without having seen it printed) 凭记忆，不看乐谱
215.have an ear for (=have keen recognition of sounds esp. in music and language.) 对……有鉴赏力
216.a word in one‘s ear 私房话，秘密话
217.on earth究竟，到底，全然
218.with ease (=easily) 容易，不费力
219.at (one‘s) ease ( = without worry or nervousness) 自在，不拘束
220.put sb. at his / her ease (=free sb. from worry or nervousness) 使某人感到无拘束
221.economize on (=save sth. instead of being wasteful) 节省
222.have an effect on 对……有影响
223.be in effect (=be in operation) 有效
224.go into effect 生效。(近：come into effect; take effect; be brought into effect)
225.in effect (=in fact， really) 实际上
226.give effect to (=carry out) 实行，使……生效
227.to no effect不起作用，没有取得任何效果
228.(be) of no effect (=useless) 无效
229.to the effect that大意是……，主要内容是……
230.to that effect是那个意思的……