A:4π
B:6π
C:8π
D:9π
Most of the time, he has no trouble ______________ the people from different countries.
有下列说法,其中正确说法的个数是( )
(1)无理数就是开方开不尽的数;
(2)无理数是无限不循环小数;
(3)无理数包括正无理数、零、负无理数;
(4)无理数是无限不循环小数.
Please call tomorrow (明天).