________regular exercise is very important, it's never a good idea to exercise too close to bedtime.

A．If               

B．As  

C．Although        

D．Unless

?????? regular exercise is very important.It’s never a good idea to exercise too close to bedmme.

A.If??????????????? B. As?????????????????? C.Although ????????????? ????????????? ???? D.Unless

        regular exercise is very important.It’s never a good idea to exercise too close to bedmme.

A.It          B. As       C.Although      D.Unless

       regular exercise is very important.It’s never a good idea to exercise too close to bedmme.

1. A.
   It
2. B.
   As
3. C.
   Although
4. D.
   Unless