A:垂体
B:甲状腺
C:胰脏
D:性腺
下列关于溶液的说法正确的是( )
Jin Yong is one of the greatest and oldest _______ writers. He is still _______.
函数f(x)=lnx-2x的零点所在的大致区间是 ( )
如图,矩形ABCD中,AB=3,BC=5.过对角线交点O作OE⊥AC交AD于E,则AE的长是( ).