Do One, Teach One, Kill One - S2-E3
Continuity mistake: As Chloe moves backward away from the fence while talking to Susan, we can see her friend Ruth in the convertible, sitting up on the back of the seat. In one shot Ruth completely disappears but reappears again, all in the course of a few seconds.
It's Not Easy Being Greene - S2-E13
Continuity mistake: Carter goes into the faculty dining room to talk to Peter and Dr. Vuselich - he has a brown strap around his neck (with his stethoscope) which changes position several times during the scene, even though he never touches it.
Continuity mistake: Susan is at home, making drinks for Mark and her - she pours them drinks from the blender and leaves a little bit of liquid in the blender. They head for the living room and the blender suddenly has about 3 inches of liquid in it.
It's Not Easy Being Greene - S2-E13
Continuity mistake: Harper and Carter are in bed and his hand is bunched under the bedspread several inches from her hand. The next shot shows his hand is up by hers, touching her bottle of water, with no time for natural movement.
Baby Shower - S2-E15
Continuity mistake: At the beginning of the show, Peter is scraping the ice off his windshield, but the scraped pattern we see from inside the car is different from the pattern outside. When the car won't start, he gets out, and more of the windshield has been scraped in the meantime.
Continuity mistake: While Doug is giving CPR to the kid that was stuck it is pouring rain and everyone is soaking wet. When he runs with the kid and cop to the ambulance, it is no longer raining and they are all dry.
Continuity mistake: Jerry is eating a hot dog while he talks to Carter. He is holding it with one hand. The shot changes and suddenly he has two hands on it but then the next shot goes back to the first position.
Continuity mistake: Peter is standing next to the bed of a the little girl who was hit by a car, talking to her parents. Suddenly there is a paper in his hand which hadn't been there in the shots before.
Answer: Take care of your dad.