I worked hard because I really wanted to pass the examination.<br/><br/>---<br/><br/>Can i change it,<br/><br/>replaced by therefore<br/>1.) Therefore I really wanted to pass the examination; I worked hard. <br/><br/>a comma was added after therefore<br/>2.) Therefore, I really wanted to pass the examination; I worked hard. <br/><br/>used "Due to"<br/>3.) Due to really wanted to pass the examination, I worked hard. <br/><br/>let me know if you have a better example, please advice me <br/><br/>Thank you, Experts