B-35：buckle down on 开始认真地干
A：I don't know why you change your mind. You are looking forward to traveling abroad, aren't you?
A: 我不明白你为什么改变主意。你不是一直渴望到国外去旅游吗？
B: Yeah. But I must buckle down on my study this holiday. If I fail the entrance examination, my parents will be very disappointed.
B：是的。但是这个假期，我必须努力学习。如果我没有通过升学考试，父母一定会很失望的。
A: I see.
A：我明白了。
