We can never expect ______ bluer sky unless we stop______ industrial waste going into _____ atmosphere.

While the government says there is a(n) ________supply of houses, prices of apartments have been going up these years.[ ]

Every time he meets with hard problems, he always ________ his parents. [ ]

Fishing and seafood harvesting has been forbidden along the coast of Galicia, forcing many fishermen ______.

The earth（地球） is our home, and we must _____ it clean.