— How ____ the people in Yunnan?
— Very friendly. [ ]
A. were
B. was
C. is
D. do
答案:A
尿素合成过程的限速酶是
A.精氨酸代琥珀酸裂解酶B.鸟氨酸氨基甲酰转移酶C.精氨酸代琥珀酸合成酶D.氨基甲酰磷酸合成酶E.精氨酸酶
CA6140型车床,车削米制螺纹和米制蜗杆时,挂轮传动比都应是63:75。( )