188.[答案]D. hang on.[注释]hang on(=hold fast, keep hold)牢牢抓住，抓紧不放：Help! I can't hang on much longer.(救命啊!我支持不住啦。)keep on(doing sth.)继续(做......);catch on 理解;count on 指望，依赖。本题译文：杰克差点从悬崖上掉下来，但得以抓住不放直到得救。

187.[答案]B. scarcity.[注释]scarcity(=the state of being scarce)缺乏;不足(指原本充足之物暂时在数量上的缺乏)。例如：The scarcity of fruit was caused by the drought.(水果的供应不足是干旱所引起的。)rarity(=sth. uncommon, unusual or sth. valued because rare)珍稀，稀少：Snow is a rarity around the equator.(雪在赤道周围是罕见之物。)invalidity(=making weak by illness; not suitable for use)无效性，丧失工作能力。Variety(=difference of condition or quality)变化，多样化。

　本题译文：目前席卷这一地区的暴风雨今后肯定会引起蔬菜短缺。

186.[答案]A, release.[注释]release(=allow news to be published)发布(新闻)：Details of the scheme have not yet been released to the public.(这项计划的细节尚未向公众发布。)relieve 1)减轻(痛苦，紧张情绪等)：What will relieve a headache? This will help to relieve our hardship. 2)使放心，使宽慰：The good news relieved us, for we had been very anxious. 3)赈济，救济：The fund is for relieving distress among the flood victims. 4)relieve...from(of)解除，免除; a. This medicine will help to relieve you from your pain. b. He was relieved of his duties.retain(= keep; continue to have or hold)保持，继续保有：1)She retains a clear memory of her schooldays. 2)You must retain your tickets.

185.[答案]D. moderate.[注释]moderate(=make or become less violent or extreme)节制，缓和，减轻。

184.[答案]D. model.[注释]model此句中意为“(飞机的)模型”。

183.[答案]C. missed.[注释]miss doing sth.没有做某事：I missed seeing the film when it was shown at school.(学校放映那部电影时，我没有能去看。)

182.[答案]C. at random.[注释]at random(=without aim or purpose)随便地，胡乱地：His clothes were scattered about the room at random. By accident意外地;on occasion偶尔;on an average平均计算。

181.[答案]A. purpose.

　[注释]on purpose是介词习语，意为“故意地”。如用intention,则应说by intention故意地。

180.[答案]A. recall.[注释]recall(=bring back to the mind)想起，回忆起：But I really cann't recall your name at his moment.

　Remind sb. of ...使......想起：1)The photo reminds me of my late father.(这张照片使我想起已故的父亲。) 2)The sight of the clock reminded me that I was late.Remind sb. to sth.提醒......做......;Please remind me to write the letter.

179.[答案]D. realised.[注释]realise sth. by doing sth. else通过做......来实现.......。