Jenny often goes to school by bus.珍妮经常乘公共汽车去上学。主谓结构,一般现在时。因为没有助动词,需要加do或者does。主语是Jenny,换成代词是she,所以加单数助动词does帮助否定。Jenny doesn't often go to school by bus. 翻译;珍妮不经常乘公共汽车去上学。