We don’t know the reason _____ he didn’t accept the job.
What the science teacher does and says ____ of great importance to college students.
The year 2007 ______ remarkable changes in Changzhou’s landscape.
The children were catching butterflies in the garden. Some caught a lot, and others caught _______ at all.
How wonderful to go away for a month, _____ all worries and responsibilities!
Health officials have tried to raise _______ about the H1N1 flu among all people.