Exercising an hour every day is ________useful way to ...
Exercising an hour every day is ________useful way to ...
真诚求教!Exercising an hour every day is ________useful way to help us keep healthy.You're really right,but I am too busy___________to exercise.
A.a,to study B.an,studying C.a,studying
如果选A,变成too...to...句型不行吗?