1.____{arrive} at the airport on time ,he got up very early

1.____{arrive} at the airport on time ,he got up very early
2._____{compare} with life in the past,life now is more comfortable
3.I don't think bread is so ____ {taste} as cake
4.Life on Mars is difficult ____ {imagine}
5.The scientists mapped the _____ {outside of an object} of the moon
6.There will be f_____ people on Mars than on Earth{意思差不多就是比地球少}
7.Will the pollution be s_____ on Mars?
8.They will live a l___ life on Mars than on Earth