Babysitting

i am 14 years old and i babysit 3 adopted boys a five year old, seven year old, and eight year old. everyday i babysit them they are so disrespectful and do things that they know they shouldn’t so and say things they know they are not allowed to. i have been babysitting them for a while and they continue to get worse. the eight year old is getting better but i don’t know how to handle the other two i feel so helpless. they play in their water and purposely say yes sir to get on my nerves and cause they know i won’t do anything but tell them to stop. please help!!! they have many things to do but they ruin their chances with it..