单项选择题
A．Tinkling sound of a coin dropping. B．Clinking sound of keys. C．Tapping sound of his typewriter. D．Creaking sounds.
A．don't care about emergencies B．are used to sirens C．are attracted by sounds D．don't hear loud noises
A．think of money B．look at each other C．pay: attention to it D．stop crossing the street