选择恰当的应答语( )
A:No, I don't.
B:No, she didn't.
C:Yes, I did.
D:Yes, I do.
血液在血管中的流向是( )
设OA→=a→,OB→=b→,OC→=c→,当c→=λa→+μb→(λ,μ∈R),且λ+μ=1时,点C在( )