当乘客电梯额定速度为2.0m/s<V≤2.5m/s时,其平均加减速度不应小于()
A.0.65m/S
B.0.75m/S
C.0.85m/S
D.1.5m/S
参考答案:A
混合气体的初始压力对爆炸极限的影响较复杂,下列相关叙述不正确的是( )。
A.在0.1~2.0MPa的压力下,对爆炸下限影响不大,对爆炸上限影响较大B.当压力大于2.0MPa时,爆炸下限变小,爆炸上限变大,爆炸范围扩大C.初始压力增大,气体爆炸极限也变大,爆炸危险性增加D.当混合物的初始压力减小时,爆炸极限范围扩大
用适当的介词填空。
1. Amy is sitting ______ Cara and Doris.
2. Go _____ the street, and you will see the bookstore on the right.
3. Do you help ______ home?
4. We go ______ the bakery when we walk to school.
5. Danny has written the way _____ a piece of paper.
6. There's a school ______ our house.
7. I'll put my letter ______ an envelope and post it.
8. I like to play hockey ______ winter.
9. He is pointing ______ the right.
10. The wind blows the clouds ______ the sky.