影响爆炸极限的因素有哪些？
参考答案：
影响爆炸极限值的因素主要有：初始温度、初始压力、惰性介质及杂质、混合物中氧含量、点火源等。
选词填空:
1. We ______ (arrive, get to) here at 8:00 every day.
2. The hotel is ______ (in, on) the Fifth Street.
3. Can you tell me the ______ (street, way) to the hospital?
4. The post office is ______ (across, cross) from the school.
5. Our teacher sits ______ (in front of, in the front of) the classroom on the chair.
在工程网络计划执行过程中，如果需要确定某工作进度偏差对总工期的影响，应根据( )的差值确定。
A．自由时差与总时差
B．总时差与进度偏差
C．自由时差与进度偏差
D．时距与进度偏差
