ENERGY-SAVING BULBS SHOULD ... TO SAVE ETECTRICITY.A.USE B. USED C...

88. - 400 CAU TRAC NGHIEM ON TAP ANH 9 4OO CAU TRAC NGHIEM ON TAP L9
400 CAU TRAC NGHIEM ON TAP ANH 9 4OO CAU TRAC NGHIEM ON TAP L9

88.

Energy-saving bulbs should ... to save etectricity.

a.

use b. used c. be use d. be used