按我国GB2828标准，对商品的检验首先进行“正常检验”，如果检验结果符合质量要求，则进入“放宽检验”，否则，进入“加严检验”。（）
参考答案：对
—Jack, this is the third time that you have been late this week.
—Sorry, sir, but I was ____ for 15 minutes on the way here in the traffic jam.
A．held up
B．put up
C．taken up
D．given up
肽键的性质是（）
A.二硫键
B.配价键
C.酰胺键
D.酯键
E.氢键
