A．Buy tennis shoes and tennis rackets.
B．Find where the toys are sold．
C．Take the elevator to go upstairs.
D．Ge! enrolled in a tennis training course．
A．They should make several observations of the same child.
B．They should observe several children at the santo time.
C．They should find an ideal location for the observations.
D．They should observe at the time most convenient for themselves.
A．The behavioral patterns of children at different time.
B．The influence of environment on a child's behavior.
C．The impact of observation on a child's behavior
D．The interactive influence of children's behavior.