题目

某同学在进行“观察多种多样的细胞活动后，做出如下描述，其中正确的是（） A . 观察人血涂片时无需染色即可观察到呈紫色的白细胞 B . 牛神经细胞的胞体在光学显微镜下不可见 C . 无法观察到狗骨骼肌细胞中的细胞核 D . 可观察到蚕豆叶下表皮中的气孔 答案：D Nick Petrella is a doctor in Montreal. He works 60 hours a week. He takes care of 159 patients a week in the hospital and at his office. He’s been a doctor for ten years.     Dr. Petrella gives his patients good medical advice. But he doesn’t just tell his patients what to do. He also sings to them on television! Dr. Petrella has his own TV show. The show is in Italian, English and French. The doctor starts the show with a song and then gives medical advice. He explains a medical problem or disease in simple language. After that, he sings another song.     Dr. Petrella produces and performs in his own show every week. The program is very popular with his patients and with people who enjoy his singing. His dream is to perform（表演） in Las Vegas. His favorite songs are love songs, and he has a compact disk of love songs that he wrote. Dr. Petrella says, “I always loved to sing. All my problems are gone when I sing.” But when Dr. Petrella was young, his father didn’t want him to be a singer, So he went to medical school.     Some people tell Dr. Petrella he can help people more as a doctor. But Dr. Petrella says he helps people when he sings, too. “I like to make people smile. Sometimes it’s difficult to make a sick person smile. Medicine and entertainment（娱乐） both try to do the same thing. They try to make people feel good.” 1. Dr. Petrella works 60 hours a week, because he ____________________.           A. gives his patients medical advice         B. takes care of 159 patients a week C. sings on television                             D. has his own TV show 2. Dr. Petrella ___________, so he is called a singing doctor.          A. has been a doctor for ten years             B. always loved to sing       C. is popular with his patients                D. also sings to his patients on TV    3. In his TV show, Dr. Petrella ___________________.        A. sings and gives medical advice                 B. sings about different diseases C. starts to explain diseases with a song        D. sings love songs he wrote 4. Dr. Petrella’s show is popular ________________.   A. in Las Vegas.                                        B. at medical school  C. with people who like his singing             D. with patients in Montreal   5. Dr. Petrella says he likes to __________________.   A. help people sing                           B. make people feel better C. do the same thing                       D. make difficult people smile