— People should stop using their cars and start using public transport.

— ________. The roads are too crowded as it is.[      ]

A. All right  

B. Exactly

C. Go ahead  

D. Fine

下列属于蛋白质和氨基酸代谢试验的是（）

A.吲哚试验

B.甲基红试验

C.七叶苷水解试验

D.硝酸盐还原试验

E.枸橼酸盐利用试验