低钙血症常见于:()
A.甲状腺功能减退
B.肾功能衰竭
C.严重腹泻
D.甲状旁腺功能亢进
E.频繁呕吐
参考答案:B
Please tell them the story ____________ the tortoise and the hare.[ ]
A. for
B. about
C. in
等比数列{an}中,已知a9=﹣2,则此数列前17项之积为( )
A.216
B.- 216
C.217
D.﹣217