2016高考训练题。阅读理解。
阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。
The baby is just one day old and has not yet left hospital. She is quiet but alert（警觉）. Twenty centimeters from her face researchers have placed a white card with two black spots on it. She stares at it carefully. A researcher removes the card and replaces it by another, this time with the spots differently spaced.
