The country has been ______ war with its neighbor for almost ten years.
In that school, English is compulsory for all students, but French and Russian are ______.
Would you like tea or coffee? --_____, thank you. I’ve just had some water.
We can never expect ____ bluer sky unless we create _____less polluted world.
—Can I use your laptop for a while? —; any how I am not using it now.
What the science teacher does and says of great importance to college students.