I'm afraid I forgot ___ him your number. [ ]
A.tell
B.to tell
C.say
D.to say
答案:B
用氟离子选择电极法测得某溶液E=290mV,相应的氟离子浓度为2.31mg/L,已知其E-logC的斜率为59mV,测得另一溶液的E=231mV,其相应的氟离子浓度为()
A.5.9mg/L
B.231mg/L
C.23.1mg/L
D.290mg/L
E.2.31mg/L
操纵子是由______、______和______三部分组成。