1、I'm going to have to knuckle down to some serious study.
我得開始認認真真地學習了。

2、He managed to knuckle down to his lessons long enough to pass his examination.
他在離考試還有足夠長時間的時候就開始認真學習，從而通過了考試。

3、He would not knuckle down under their pressure.
他不會在他們的壓力下屈服的。

4、You 'll really have to knuckle down if you want to pass the examination.
如果想通過考試，你確實應(yīng)專心學習。

knuckle down翻譯