Dentists say it is important to find soft toothbrushes made especially for babies and to use them very gently.

VOA: special.2009.03.11

And especially when we consider it, what tends to be important is the size of wavelength in relationship to its environment.

特别是当我们考虑它的时候，波长的量级和它所处环境,的关系就显得非常重要。

麻省理工公开课 - 化学原理课程节选

And especially when we consider it, what tends to be important is the size of wavelength in relationship to its environment.

特别是当我们考虑它的时候，波长的量级和它所处环境,的关系就显得非常重要。

麻省理工公开课 - 化学原理课程节选