题目

遗传学上的密码子是指A. DNA一条链上相邻的3个碱基B. mRNA上决定一个氨基酸的3个相邻碱基C. tRNA一端的3个碱基D. DNA分子上3个相邻的碱基对 答案：【答案】B【解析】试题分析：遗传学上的密码子是指mRNA上决定一个氨基酸的3个相邻碱基；tRNA一端的3个碱基构成反密码子，DNA分子中碱基的排列顺序代表遗传信息，所以选B。Dear Mrs. Hogget     You may remember that we have discussed the noise your children make while practicing their musical instruments(乐器)． You agreed to make sure that they would stop practicing in the evenings．     You can imagine my astonishment, then, when I realized that nothing had changed and the situation was continuing as before． I find it difficult to stay in the house and invent any excuse to go out for the evening to be away from the terrible noise． Much as I like music, I have had enough, and to be frank (坦诚的), I am not prepared to put up with the situation any more．   I think it high time you realized your duty as a member of the community (团体), and I must warn you that unless you do something about the situation I will be forced to take legal (法律) action． I have sent a copy of this letter to my lawyer． 1. In their discussion, Mr. Barge________． A．expressed his astonishment B．showed his anger to Mrs. Hogget C．made Mrs. Hogget’s children not practice their musical instruments in the evenings． D．was told that he wouldn’t be troubled by the noise in the evenings any more 2．Mr. Barge feels angry because ________． A．Mrs. Hogget’s children play their musical instruments so badly B．Mrs. Hogget’s refused to talk about the noise problem with Mr. Barge C．Mrs. Hogget does not allow her children to play their musical instruments in the evening D．Mrs. Hogget has broken her promise 3.Which of the following statements is correct according to the passage? A．Mr. Barge is not fond of the music． B．Mr. Barge likes music, but he doesn’t like the noise． C．Mr. Barge often goes out in the evenings to give music lessons． D．Mr. Barge expects a reply from Mrs. Hogget． 4. Mr. Barge is prepared to________ A．help Mrs. Hogget to persuade her children not to play their musical instruments any more B．take his duty as a member of the community C．sue (诉论)Mrs. Hogget for the noise made by her children D．force Mrs. Hogget to send a copy of his letter to her lawyer