IF WE KEEP ON …………. MORE AND MORE MOTOR VEHICLES, WE ……… OUT OF OIL...

4. - DE KIEM TRA TIENG ANH 9HKII LAN 1
DE KIEM TRA TIENG ANH 9HKII LAN 1

4. If we keep on …………. more and more motor vehicles, we ……… out of oil.

a. using / would run b. using / run c. using / will run d. to use / will

run