,but it is also a great way to lower the number of greenhouse gases in the air.
A. Not only a fun thing is it to do
B. Not only a fun thing to do it is
C. Not only it is a fun thing to do
D. Not only is it a fun thing to do
网友回答
A. Not only a fun thing is it to do
B. Not only a fun thing to do it is
C. Not only it is a fun thing to do
(答案→)D. Not only is it a fun thing to do
解析：句意：这件事情不但是一件有趣的事，而且是一种降低空气中温室气体的有效途径。否定词位于句首时，应使用部分倒装。