Tags are very common in spoken English, and have many functions. One of the common functions is to start a conversation or help keep it going. The two basic rules about tag questions are:1  If the statement is negative, the tag must be positive.ags are very common in spoken English, and have many functions. One of the common functions is to start a conversation or help keep it going. The two basic rules about tag questions are:
The average cost for a community to fluoridate its water is estimated to range from approximately $0.50 a year per person in large communities to approximately $3.00 a year per person in small communities. For most cities, every $1 invested in water fluoridation saves $38 in dental treatment costs.55 âFor most cities, every $1 invested in water fluoridation saves $38 in dental treatment costs.â It can be calculated from these data that the average lifetime cost per person to fluoridate a water system is less than the cost of one dental filling.
1 For out-of-district or out-of-state students, tuition can cost $100-$550 or more per credit unit, or $300-$1,650 to take one three-unit class. At Century College in White Bear Lake, MN, tuition and fees for two 15-unit semesters total $5,356 for general classes, $5,540 for dental hygiene courses and $5,846 for the nursing program. 2  Tuition is just one of many college expenses.