-I think everyone should play a part in saving our environment..
-I agree. For example, there will be less air pollution _______ we drive less.
A.if B. so C. though
We _______ for a picnic if it ______ rain this Sunday.
A.will go; doesn't B. will go; won't C. go; doesn't
You must stop if the traffic light _______red.
A.was B. is C. will be D. has been
-What ______ if you don't go to school today?
-The teacher will be angry with me.
A．should happen B．are you doing
C．will happen D．do you do
Our world will get better and better ______ each of us lives a greener life.
A.before B. if C. though D. until