構成素
代用(pro-form substitution または replacement)では、テストしたい箇所を代名詞など(例えば it、he、there、here)に置き換える。
I don't know the man who is sleeping in the car. → I don't know him. → *I don't know him who is sleeping in the car.
The student met a girl from New York in the park. → The student met her there. → He met a girl from New York there. → He met her in the park. → *He met her from New York there. → He met her there.