He studies hard yet he always fails.

他学习努力，可是考试总不及格。

It will be to his advantage if he studies hard.

假如他努惫学习,就会对他有利.

One can't learn English well unless he studies hard.

如果不努力，就学不好英语。

He studies hard lest he should fail in the next exam again.

他怕在下一次考试中再不及格，因而努力学习。

He studies hard and he often reads books until late at night.

他学习十分刻苦， 经常披卷到深夜。