I have never seen this subject before but I have recently seen this on an internet site exercises"grammarstation.com" quiz section....<br/><br/>That is compuond subject with I<br/><br/>It says we can't start the sentence with this """"" <del>I and Mary</del> will go to the supermarket soon.<br/><br/>Instead the true starting is......................"""""""""-Mary and I - will go to the supermarket soon.<br/><br/>What do you say operators..teachers...