______is the study of speech sounds in language or a language with reference to their distribution and patterning and to tacit rules governing pronunciation.

A．substitutes can take the responsibilities of parents.
B．it’s acceptable to let substitutes look after children.
C．perhaps substitutes can play a better role than parents.
D．parents should be cautious to choose substitutes.

A．Group leaders.
B．Television.
C．Baby-sitters.
D．Play groups.