已知有5个红球,3个黑球,有放回的抽取,则第二次抽到黑球的概率是()。
A.3/5
B.2/7
C.3/8
D.2/3
参考答案:C
There is elephant there. Near elephant,there is tall tree.
A.an; an; a
B.a; the; a
C.an; the; a
D.an; the; the
气象资料包括那些内容?