What is the difference among many "if" words?
如果: simply means 'if'. For example, 如果我知道，我就会告诉你。 If I knew it, I    would tell you.
  如： is short for 例如, meaning 'for example', 'like' or 'as'. It's used    when you give some examples. For example (如)： 手字可以和很多字组词，如：手机.
  假如: supposing or in case. For example: 假如生活欺骗了你, in case/supposing    life deceived you.
  只要: only if or as long as. For example: 只要你做完工作就可以走了。You could go as long as you finish the work.
  即便: even if/even though. For example: 即便是老板，我也不怕。 Even though he is    the boss, I wouldn't fear.
  要说: as for; want to say something; For example, 要说他这个人，没人知道。As for    this person, no one knows. 我没有什么要说。 There is nothing I want to say.