Where's my pen? [ ]
A. It's in the desk.
B. It's under the desk.
C. It's on the desk.
答案:B
若方程2ax2-x-1=0在(0,1)内恰有一解,则a的取值范围是______.
用于细菌培养的尿液采集的方法中标本应注意采集()
A.初段尿
B.中段尿
C.末段尿
D.随意采集
E.可以不用无菌操作