趁来得及,立刻采取行动!
at once before it's too late!
Jack looked through the (介绍)about the book before he decided to buy it.
Students should answer questions loudly and (清楚)in class.
Do you need to (讨论)the problem in groups?
Please keep (安静)when you are in a library.
不要怕犯错,我们可以从错误中学到东西.(learn from)