若ab<0，则|a|+|b|=|a-b|，若ab>0，则|a|+|b|=|a+b|。[ ]
正确
We hope you _____ a happy holiday in Hong Kong. [ ]
A. to have
B. having
C. had
D. will have
采用级联方式使用8259中断控制器，可使它的硬中断源最多扩大到______个。
