1-Whether the car will be ready depends on the mechanic.<br/>2-It depends on the mechanic whether the car will be ready or not.<br/><br/><i>3-She wonders whether the teacher will attend.</i><br/><i>4-She wonders whether the teacher will attend or not.</i><br/><br/>Is there a difference?<br/>Are all these statements correct?<br/><br/>Please explain and if possible with examples and references.