WHAT CAN WE DO TO SPEND LESS _________LIGHTING

10. - DE THI HK 2 CO DAP AN TIENG ANH 9 DE THI HOC KY 2 CO DAP AN
DE THI HK 2 CO DAP AN TIENG ANH 9 DE THI HOC KY 2 CO DAP AN

10. What can we do to spend less _________lighting?

A. in B. on C. about D. of