如果空气中含有硫化氢气体,用光学瓦斯检定器测定瓦斯时,应再加一个辅助吸收管,管内装有()可消除硫化氢影响。
A、生石灰
B、硅胶
C、碳酸钙
D、颗粒活性碳
参考答案:D
____, he sometimes makes mistakes.
A.Though he is careful teacher
B.As he is careful
C.A careful teacher as he is
D.Being a careful teacher
网络词汇“菜鸟”是表示()。
A.素食性鸟类
B.温柔
C.食用性鸟类
D.新手