Unit3b Entering a market
pledge: n. 1、a serious promise；2、a sum of money or sth valuable that you leave with sb to prove that you will do sth or pay back money that you owe；v. to formally promise to give or do sth；
aviation: n. the designing, building and flying of aircraft；
rarity:n. a person or thing that is unusual and is therefore often valuable or interesting；
pledged investment：合同投资，允诺投资
strength：n.强项，优势
literature：n. 印刷广告，产品宣传资料
advisable：adj.最好的
dead tree：纸质的
imperative：adj.极其重要的，必要的，命令式的
discourteous：adj. 不礼貌的，失礼的，粗鲁的
small talk：闲聊
audio-visual aids：视听设备，视听教具
verbal agreement：口头约定，口头协议
pasta：n.意大利面食
alternatively：adv.或者