防毒面具不适用于（）、有毒气体成份不明或（）的环境。
参考答案：缺氧、浓度较高
填写下列数词的序数词。
1. My birthday is on October (two).
2. My grandmother's birthday is on January (one).
3. His birthday is on March (twelve).
4. Mary's birthday is on November (four).
5. John and Jane's birthday is on April (three). They're twins.
对于一时无法确定腹部内脏有无损伤的病例，病情观察的内容包括哪四个方面?
