This text contains a detailed list of the requirements for the Grade 1 Theory of Music examination, information that may be needed in the context of the examination, specimen questions and exercises, and guidance on their solutions. It provides a sound foundation for anyone wishing to understand music theory as it is used in practice. A wide variety of music examples are used to illustrate the texts and to provide exercises.
I bought this one day at a library. If you are studying music theory, this is a good resource to start with. If you are confused, I recommend asking your teacher for a explanation.