WHAT CAN WE DO TO SPEND LESS ... LIGHTING

590. - 1000 CAU TRAC NGHIEM TIENG ANH ON THI THPT QUOC GIA CO DAP AN
1000 CAU TRAC NGHIEM TIENG ANH ON THI THPT QUOC GIA CO DAP AN

590. What can we do to spend less ... lighting?

A. about

B. on

C. in

D. of