A:skill
B:talent
C:authority
D:expert
若a∈0,3,b∈0,2,函数fx=x2-2ax+b2有零点的概率为()
Most ____(申请人) know they have little chance of getting a visa.
afternoon ____ a b a f t e r n o o n o n
下列这些水中生活的动物中,哪一组都是无脊椎动物?( )