将各种氨基酸结合在一起形成肽链的结构被称为()
A.氢键
B.肽键
C.共价键
D.非共价键
E.二硫键
参考答案:B
涡流探伤仪检测线圈直接影响到检测结果,主要体现在那些方面?
—Tom didn’t come last night,did he?
—No.I _______ have waited for him.A whole night was wasted.
A.would
B.should
C.couldn’t
D.needn’t