题干

某混合气体可能含有CO、H2、CO2和H2O(气)中的一种或几种.为验证其组成,同学们进行实验的装置和现象如下(假设气体均吸收完全),常见干燥剂有:浓硫酸、氯化钙、碱石灰、生石灰、氢氧化钠,后三种还可以吸收二氧化碳,判断正确的是(   )

A:气体中一定有氢气

B:一定有一氧化碳

C:一定有二氧化碳

D:一定有水

上一题 下一题 0.0难度 选择题 更新时间:2019-01-14 06:46:44

答案(点此获取答案解析)

A,B

同类题3

语法填空

                         Gift from a stranger

    My local supermarket is always busy. The first parking space I found was convenient, but I'd noticed a woman in a blue car circling for a while.____ I was in a good mood, I let her have it. On the edge of the car park I backed into the next available spot—it was a tight fit.

    Pretty soon I'd made my way through the supermarket and was back in the fresh air. Feeling good, I____(empty) my purse change into the hands of a homeless man and helped a struggling woman reverse park(倒车).

    Just as I approached my car, 1 saw the woman I'd let have my car space earlier. She was giving me ____ odd look—half puzzled, half intent (热切的). I smiled and wished her a pleasant day. As I squeezed back into my car, I spotted the same lady ____ (look) in at me. "Hello," she said, hesitantly. "This _____ sound crazy but I was on my way to drop some of my mother's things off at the charity bins.” You are just so much ____ her.” You helped those people, I noticed, and you seemed so happy.” She looked at me meaningfully and passed a box in through the window. “I think she would like you to have it.”____ (shock), I took it from her automatically. She smiled and walked away.

    After a pause, I opened the box. Inside was a beautiful gold necklace with a large grey pearl. It was ____ (nice) gift I'd ever received, and it was from a complete stranger. The necklace was around my neck, a warm reminder of human kindness.