Muscles are unique fibers, because they can（）

单项选择题Intelligent use of the muscles means that （）

A．one always knows what his muscles are doing
B．one performs simple actions without working
C．one's muscles are used only to the extent necessary for each action they perform
D．one improves muscular action consciously

单项选择题In what way did the writer find the White family completely different from her own（）

A．Her parents were not as loving as the Whites.
B．Hers were very strict parents while the Whites were too kind.
C．When something went wrong the Whites didn' t blame their children for it.
D．When aomething had happened, her parents wanted the children to learn a lesson.