下列说法正确的是（） A．某气体通入紫色石蕊试液，紫色石

搜题请搜索小程序“爱下问搜题”

问题选择题

下列说法正确的是（　　）

A．某气体通入紫色石蕊试液，紫色石蕊试液变红，那么该气体一定是二氧化碳气体

B．实验室可以用块状石灰石和稀硫酸制取二氧化碳气体

C．构成二氧化碳气体的微粒和构成干冰的微粒不同

D．一个二氧化碳分子中共含有三个原子核

答案

A、不一定是二氧化碳，气体溶于水后使溶液显酸性的都可使石蕊变红，故A错误．

B、实验室常用块状石灰石和稀盐酸制取二氧化碳气体，因硫酸钙微溶，不用硫酸，故B错误．

C、干冰是固态二氧化碳，则构成二氧化碳气体的微粒和构成干冰的微粒相同，故C错误．

D、因一个二氧化碳分子中有2个氧原子和一个碳原子，含有三个原子核正确，故D正确．

故选D．

完形填空

I used to be a very self-centered（自我中心的） person, but in the past two years I have really changed. I have started to think about other people    I think about myself. I am happy that I am becoming a different person.
I think my    started when I was at Palomar College. At first, I just wanted to get my degree（学位）and be left alone. I thought I was smarter than everyone else, so I    talked to anyone in my classes. By the end of my first semester, I was really    . It seemed as if everyone had made friends and was having fun, except me. So I had a（n）    . I started asking people around me how they were doing, and if they were having trouble, I would    to help. That was really a big step for me. By the end of the year, I had several new friends, and two of    are still my best friends today.
A bigger cause of my new    , however, came when I took a part-time job at a Vista Nursing Home. One old lady there who was badly ill became my    . Every time I came into her room, she was so    because she thought I was her daughter. Her real daughter never    her, so I took her place. She let me    that making others feel good make me feel good, too. When she died, I was    , but I was very grateful（感激的）to her.
I think I am a much better person today than I used to be, and I hope I will not    these experiences. They have taught me to    about other people more than about myself.

查看答案

单项选择题

男患，64岁。自右背部放射至右腋下疼痛8个月，右下肢乏力5个月，加重伴小便费力1个月。查体：右下肢肌力3级，左下肢4级，双下肢肌张力增高，腱反射右（++++）、左（+++），T2以下痛觉减退，左侧明显，右下肢振动觉差，双侧Babinski征（+）。下列哪一种疾病最有可能（）。

A.急性脊髓炎

B.脊髓空洞症

C.急性脊髓硬膜外脓肿

D.脊髓髓外肿瘤

E.脊髓髓内肿瘤

查看答案