You have to scrupulously check and cross-check everything you hear.你必须仔细检查并多方核对你所听到的每一件事。You should cross-check your answers with a calculator.你应该用计算器检查一下你的答案。I had to look twice and cross-check with another file to make sure I hadn't misread it.我得检查两遍，并且还要根据另一份文件来反复核对以确保我没有误读。