答案： well
be well worth doing 大有可为
eg.
Whatever is well worth doing should be done well.
凡是值得做的事情都应做好.

祝你学习进步,更上一层楼! (*^__^*)
不明白的再问哟,请及时采纳,多谢!为什么不填VERY固定搭配呀，不能用very