If you are a vegan, then you do not eat meat.
If you do not eat meat, then you are a vegan.
If two angles are congruent, then they have the same measure.
If two angles have the same measure, then they are congruent.
If you add 5 and and 10, then you get a sum of 15.
If you got a sum of 15, then you added 5 and 10.
"If Cliff is thirsty, then she drinks water."
" If Cliff drinks water then he is thirsty"
If you have a coupon, then you will receive a free drink with your pizza.
If you received a free drink with your pizza then you have a coupon.
If I eat a pint of ice cream then I will gain weight.
If I gain weight then I ate a pint of ice cream.
If a polygon has four sides, then it is a quadrilateral.
If a polygon is a quadrilateral, then, it has four sides.
"If it rains, then they cancel school"
"If they cancel school, then it rains."