According to the latest investigation,most mistakes be prevented if students are careful enough.
The poet andpianist is going to give us a talk this afternoon.
We can never expect ____ bluer sky unless we create _____less polluted world.
Would you like tea or coffee? --_____, thank you. I’ve just had some water.
In that school, English is compulsory for all students, but French and Russian are ______.
Sometimes proper answers are not far to seek ______ food safety problems.