Watch The Terrible Twos and the Trusting Threes (1951) : Full Movie Online Free A study of child behavior at two and three years, showing what to expect and how parents can deal constructively with the problems they present. The film shows a group of active children in playground, nursery school and home, first at age two, and then at three. Destructiveness, tantrums, rivalry with younger children, and unreasonable fears are discussed.