Some notes on Volcanoes from Tulane University.
Some words used in here are taught at A Levels and beyond, e.g. andesitic, rhyolitic, however, otherwise many of the words should be familiar to you all at O levels.
The sections on Shield volcano and Stratovolcano will be most useful to us.
http://www.tulane.edu/~sanelson/Natural_Disasters/volclandforms.htm
tms geogies 