IF PEOPLE (SAVE/ WILL SAVE/ SAVING) ENERGY, THERE WILL BE NO SHORTA...

1. - TONG HOP KIEN THUC TIENG ANH THCS VA CAC BAI KIEM TRA THU
TONG HOP KIEN THUC TIENG ANH THCS VA CAC BAI KIEM TRA THU
1. If people (save/ will save/ saving) energy, there will be no shortage of electricity.