A:Luckily
B:Hopefully
C:Sadly
D:Unfortunately
此地一为别,____。(李白《送友人》)
下列说法中 ①-a一定是负数;②|-a|一定是正数;③倒数等它本身的数是±1;④绝对值等于它本身的数是0、1.其中正确的个数是( )
— Could you give me a hand?
— I'd love to, but I am busy at the moment.