Once you 've mastered the keys , you should practice what you 've mastered all the time .

一旦掌握了这些关键点，就应时时刻刻练习。

The children had mastered this series months ago .

这套动作他们几个月前就掌握了。

Greeks mastered the principle of imagination and association to memorize everything .

希腊人掌握了想象的原则并将之与记忆事情相联系。

I mastered the local dialect .

我精通当地的方言。

To what degree have you mastered the subject ?

你对这个学科把握到了什么程度？