You need to learn about phrasal verbs:
http://grammar.ccc.commnet.edu/grammar/verbs.htm#phrasal (Be sure to click on the word HERE to see very useful lists of these verbs.)
and
http://www.eslcafe.com/pv/
And here are several dictionary definitions of this particular phrasal verb, "break up":
http://www.google.com/search?hl=en&rlz=1C1GGGE_enUS379US379&q=define+break+up&oq=define%3A+break+up&aq=0&aqi=g1g-v2&aql=1&gs_sm=c&gs_upl=9087l9762l0l12420l3l3l0l0l0l0l281l753l0.1.2l3l0
Let me know if you have more questions about phrasal verbs or this phrasal verb in particular.
e.g.The sound was from an iceberg which was breaking up.
(What is the meaning of 'up'? Does 'up' mean 'completely'? Can we use 'breaking' without using 'up'? And does 'breaking up' mean 'melting'?)
2 answers
English is a great language. You can chop a tree down, and then chop it up.