A．Forward-pick area is a small number of locations from which it is inexpensive to pick from
B．Bulk area is a large number of locations that are convenient to pick from
C．Bulk area is used to restock the forward-pick area
D．Forward-pick area is a small number of locations from which it is expensive to pick from

A．As children develop language skills, they usually go through the same stages, but they may reach the stages at different ages.
B．Developing children may pass through linguistic stages at different ages, although they will generally pass through each stage at some point.
C．The stages that are passed through by children in language development are very consistent. However, the exact time when they hit these milestones can be different.
D．Language development is very different for different children, and there can be variation in the stages they go through.

A．杯弓蛇影
B．惊弓之鸟
C．井底之蛙
D．刻舟求剑