题干

阅读短文,从方框中选出适当的动词,并用其适当形式填空。有的需要加助动词或不定式符号(每词限用一次)。

retire   go    work   catch   stop

    Mr. Smith ____ in a police station for 42 years and he will retire this autumn. He tried to work hard in his life but he wasn't lucky enough ____even a thief.

    Last weekend, Mr. Smith ____ to buy some sugar in a shop. When he got into the shop, he suddenly saw a young man get some money from a woman's bag and walk away. He ran to the thief and at the end of a blind alley(死胡同), the young thief ____by Mr. Smith.

    “Please give me a chance, sir,” said the thief. “I'll never do that again!”

    “But who can give me a chance?” said Mr. Smith. “I____ next month and this is the first time I've caught a thief!”

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答案(点此获取答案解析)

has worked,to catch,went,was stopped,will retire

同类题5

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(1)我们在用苹果泥作原料探究果胶酶催化反应的最适条件和最适用量时,通过来确定最适值的思想方法是不变的.此类实验的观测指标可以是____ .用葡萄制做的果酒酒味纯正,放置一段时间后,发现果酒带有明显的酸味,原因是密封不严,醋酸菌进行有氧呼吸,将果酒转变成果醋.果酒发酵结束后,为方便后续使用,可将菌液转移到甘油中,与之充分混匀后,放在____ ℃的冷冻箱中保存.

(2)对分离的能分解尿素的细菌进行鉴定,在以尿素为唯一氮源的培养基中加入____ ,培养后如果PH升高,指示剂将变红,因为细菌合成的____ 将尿素分解成氨,使培养基碱性增强.

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①将样品装入透析袋中透析12h,若分子乙保留在袋内,则分子____也保留在袋内.

②若用凝胶色谱柱分离样品中的蛋白质,则分子____移动速度最快.

③若将样品以2 000r/min的速度离心10min,分子戊存在于沉淀中,则分子____ 可能不存在于沉淀中.

(4)提取胡萝卜素常用有机溶剂萃取的方法,萃取的效率主要取决于____ ,同时还受到原料颗粒的大小、紧密程度、含水量、萃取的温度和时间等条件的影响.将提取的胡萝卜素粗品用____ 法进行鉴定,鉴定过程中需用____作为对照.