A:若b∥a,a⊂α,则b∥α
B:若α⊥β,α∩β=c,b⊥c,则b⊥β
C:若a⊥c,b⊥c,则a∥b
D:若a∩b=A,a⊂α,b⊂α,a∥β,b∥β,则α∥β
Bob has got good exam results. His parents are proud of his ______.