approving careful and using a lot of effort认真刻苦的,勤奋的,勤劳的
a diligent student用功的学生
Leo is very diligent in/about his work.利奥工作非常勤奋。
Their lawyer was extremely diligent in preparing their case.律师为他们这个案子做了认真扎实的准备。
done in a careful and detailed way细致的,潜心的
The discovery was made after years of diligent research.这一发现是数年潜心研究的成果。