Put the correct noun form of the underlined verb in the gap to complete the definitions.
1.If you invent something important , this __ may become famous .
2.Something that arrives , such as a plane flight , is an __ .
3. You can say you improve something, or that you make an___ to it.
4.Something you publish , such as book or a magazine is a ___.
5.If you explain something clearly , then you are giving a clear ___.
6. Someone who trains people to do something as a ___.