—Why do you suggest the West Lake?

—I believe __beauty of ___ nature there will make__excellent impression upon you.

A．the; /; the

B．the; /; an

C．a; the; an

D．the; the; an

Measures have been taken to prevent the accidents, but much _____ for more improvement.

A．remains to be done

B．is remained to do

C．remains to do

D．is remaining to be done