Can a dash and/or a colon be used in the following?<br/><br/>This letter is written on behalf of an individual for whom I have tremendous respect: Darnell Jackson.<br/><br/>This letter is written on behalf of an individual for whom I have tremendous respect -- Darnell Jackson.<br/><br/>I forgot to bring one item with me: my helmet.<br/><br/>I forgot to bring one item with me -- my helmet.<br/><br/>Thanks.