--- I’m really hungry now.

--- That’s because you have left your lunch        .

       A．untouching                                          B．to be untouched  

       C．untouched                                           D．being untouched

--- I’m really hungry now.

--- That’s because you have left your lunch ______.

A．untouching           B．to be untouched           C．untouched        D．being untouched