Speaker A. Did you know that Whitney Houston was giving a concert last night in the townSpeaker B: ______

A．Why don't you get some tickets for us

B．I like her, but I didn't have time for the concert.

C．Why didn't you tell me about it earlier

D．Maybe we can go to see her concert some other time.

微束等离子弧焊用电流通常小于（）安培。