English Tip: prep + v ing

if you make sentence with verb comes after preposition make sure it comes in gerund form which is adding ing at the end of the word.
preposition + v ing
I go to school by walking.
learning by doing.
Can you touch your toes without bending your knees?
finish it after eating your lunch.
I'm sure she has a good reason for not being here.
you would be punish for being late.