there will be a lot more people next century.Maybe there wil

there will be a lot more people next century.Maybe there will be ____1 room only on the
earth 600 years ____2 .That will be a very serious problem.
So man is ____3 of a way to solve the ____4.
Scientists ____5 solve many problems ____6 man can live on the moon.
1.A.standing B.sitting C.sleeping D.doing
2.A.faster B.later C.earlier D.sooner
3.A.saying B.telling C.thinking D.knowing
4.A.matter B.accident C.question D.problem
5.A.may B.have to C.can D.will
6.A.before B.after C.since D.till