David was bad at his studies, so when I was told he did well in the final exam this time, I found it really ______.
It is________ for us to deal with.
There are ________ books in our school library;however,________ of them are old.
Our government are taking firm measures to make pollution________.
________ deep down in the earth,the dead forests rotted away and became coal.
—What happened to the priceless works of art? —________.