电力事故案例心得体会:in grammar ,what do we call the words"and,but,and,or"

in grammar ,what do we call the words"and,but,and,or" What do you do in summer holidays What do you in the shop? In what way do advertisements influence you? What do you see in the pictures? what do job better in America What do these countries have in common? What language do people in Canada speak? what can nuclear energy do in medical what do you usually do in the morning?