He always goes to school _____ bike, but sometimes ______ the school bus.[ ]

We’ll have a class meeting. Don’t leave the classroom ______ 6 o’clock. [ ]

Since nuclear(核) pollution broke out in Japan, in March,2011,we are all _____ of it very much.

Look! There is _____ colour bird in the tree. ______ bird is singing.

I have to study _____a test.[ ]