would you pl explain conditional sentences and simple compound and complex sentences and their importance in eng language

Answer 1

Read all the explanations and examples:
http://www.eslbee.com/sentences.htm

And these are about conditional sentences:
http://www.ego4u.com/en/cram-up/grammar/conditional-sentences
and
http://grammar.ccc.commnet.edu/grammar/conditional2.htm
and
http://www1.icsi.berkeley.edu/~kay/bcg/lec07.html