work hard at

Some scientists are working hard at how tide can be harnessed to produce electricity.

有些科学家正在努力研究怎样利用潮汐发电。

The threat of unemployment has spurred students on to work harder at their studies.

失业的威胁促使学生更加努力学习。

Whatever you do, work hard at it and don't try to dodge the column.

论做什么事, 都要努力去做, 别偷懒。