A:称取15.36 g CuSO4,加入1000 mL水
B:称取24.0 g CuSO4•5H2O,配成1000 mL溶液
C:称取16.0 g CuSO4,加入1000 mL水
D:称取25 g CuSO4•5H2O,配成1000 mL溶液
A man says to his friend,"Guess how many coins(硬币) I have in my pocket(兜). "
The friend says. "If(如果) I guess right,will you give me one of them?"
The man says,"If you guess right,I'll give you both(两个都) of them. "
B: She plays volleyball twice a week.
设f(x)是定义在R上的奇函数,且当x>0时,f(x)=lg(x2-x),则f(-2)=( )