A:a∥α,b∥α
B:a∥α,b∥β,α∥β
C:α⊥β,a⊥α,b∥β
D:a⊥α,b⊥β,α∥β
— Who is that woman?
— She is my _____.
用科学记数法表示660 000的结果是( )