—Mr. Xu, can you tell us how to learn English well? —Sure. But remember nothing can be learned hard work.
---Your help made __________ for me to work out this problem.
---I don’t think _______ Maths is easy.
---Thanks for _________ the new chairperson.
--- He couldn’t hide his __________ at my success and said bad words about it.
--- Are you going to __________ this challenge?(挑战)