A.用滴管取细口瓶内的液体时,先将其伸入液体内,后挤压胶帽吸取液体 |
B.用托盘天平称取8.5g食盐时,先在左盘放食盐,后在右盘加砝码,移动游码 |
C.制取氧气实验结束时,先将导管移出水面,后熄灭酒精灯 |
D.检查装置气密性时,先手握试管,后将导管放入水中 |

同类型试题

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2


y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

