The old woman became aware of         when she left the market.    [ ]

A．cheating        

B．cheated    

C．being cheated    

D．to be cheated

下列成语或俗语涉及化学变化的是                                      

A．滴水成冰

B．积沙成塔

C．铁杵磨成针

D．钻木取火