Carbon dioxide ______ from burning fuels is the most common of the greenhouse gases．

A．producing                         B．having been produced

C．produced                                    D．to be produced

Carbon dioxide     from burning fuels is the most common of the so-called greenhouse gases.

      A．produced          B．producing         C．to be produced    D．having been produced

Carbon dioxide ___ from burning fuels is the most common of the so-called greenhouse gases.

Carbon dioxide ________ from burning fuels is the most common of the so?called greenhouse gases.

A．producing

B．having been produced

C．to be produced

D．produced

Carbon dioxide      from burning fuels is the most common of the so – called greenhouse gases．

       A．producing        B．having been produced    

       C．to be produced        D．produced

Carbon dioxide     from burning fuels is the most common of the so-called greenhouse gases.

      A．produced      B．producing    C．to be produced        D．having been produced

Carbon dioxide     from burning fuels is the most common of the so-called greenhouse gases.

A．produced      B．producing    C．to be produced       D．having been produced

Carbon dioxide      from burning fuels is the most common of the so – called greenhouse gases．

A．producing                                             B．having been produced   

C．to be produced                         D．produced

Carbon dioxide      from burning fuels is the most common of the so – called greenhouse gases.

A．producing                                         B．having been produced   

C．to be produced                       D．produced

Carbon dioxide(CO2)_______ from burning fuels is the most common of the so-called greenhouse gases.