HSK 5
自动
zìdòng副形
automatic; voluntarily
门开以后灯会自动亮起。
Mén kāi yǐ hòu dēng huì zì dòng liàng qǐ.
The light turns on automatically when the door opens.
Say it
Hold the button, say it, then let go.
Other HSK words sharing a character
Also free:
New in the HSK 3.0 word list at level 5.