______ WE CAN FIND OUT NEW SOURCE OF ENERGY, OUR LIFE WILL CERTAINL...
7. ______ we can find out new source of energy, our life will certainly be destroyed.
A. if
B. when
C. unless
D. even though
7. ______ we can find out new source of energy, our life will certainly be destroyed.
A. if
B. when
C. unless
D. even though