IF THEY REPLACE THESE BULBS BY ENERGY-SAVING BULBS,THEY…A LOT OF M...

40. - TIENG ANH 9 50 CAU TRAC NGHIEM 1
TIENG ANH 9 50 CAU TRAC NGHIEM 1

40. If they replace these bulbs by energy-saving bulbs,they…a lot of money every year.

A. could save B. would save C. will save D. save