When considering the cost of roofing materials, many people take into account just the shingle prices. This is incorrect, as a roof made just of roofing shingles will not work. You also need to consider all the accessories that are included in a complete roof system.
Business letters tend to have both the sender and receiver's address and the date at the top of the page and they begin with a polite salutation, such as dear Mr. and Mrs, followed by a blank line before the body or the content of the letter.
This policy will probably inform you that email is to be used only for everyday business purposes, that the computer systems at work are the property of your employer, that email may be monitored, and that you have no reasonable expectation of privacy in your use of email.