People of different cultures smile when they understand each other.（）

A．There were some creatures they did not eat.
B．They may get some of the water they needed from fruit.
C．They were afraid of poisonous creatures.
D．Female badgers did not mix with male badgers.

A．Not all toddlers use baby talk.
B．Some children need more conversation than others.
C．Language learning takes place in ordered steps.
D．Not all brains work in the same way.