Instead, their energy comes in discrete levels.

相反，它们的能量是分层次的。

Bohr proposed that electrons occupied discrete energy levels, or " orbits, " and could transition between them by absorbing or emitting precise amounts of energy as light.

玻尔提出，电子占据离散的能级或“轨道”，并且可以通过吸收或发射精确数量的光能量在它们之间进行跃迁。

An electron could switch levels, if it absorbed or released some energy -- but only specific, discrete levels were allowed, and electrons couldn’t go below the lowest level.

它可以转换能级— — 如果电子吸收或释放一些能量，但只允许特定的、 离散的能级， 电子不能低于最低能级。