从甲、乙等5名学生中随机选出2人,则甲被选中的概率为( )
A:15
B:25
C:825
D:925
用显微镜观察人血涂片,视野中可看到红细胞、白细胞及血小板(如图).下列有关三种血细胞的描述哪项不正确( )
— Jack, I call to tell you I have no time to attend your party next Friday. —What a pity!
结合材料,回答下列问题: