【填空题】原文:However, you do not have to wear a seat belt if you are reversing your vehicle; or you are making a local delivery or collection using a special vehicle; or if you have a valid medical certificate which excuses you from wearing it.译文:当然,如果有以下情况你可以不系安全带:你在______时,或者你用一种特殊交通工具进行当地的货物运送、收集时,或者你有合法的医学证明你不能系安全带时。