the problem of land erosion(侵蚀)getting more serious, the local government is searching for a way to deal with it.
______known to us,_______ increasing number of students are buried in their studies.
Not until _____,_______the diffiult problem.
She started singing to the baby and was ____ with a smile.
I did not accept any of the many offerings,because I found_____satisfactory.
You can imagine what great tuouble we had_____ the school for the blind.