单项选择题
According to the selection more than half of a person's body is composed of()
A．voluntary muscles B．involuntary muscles C．muscle fibers D．sensory nerves
单项选择题 Muscles are unique fibers, because they can ()
单项选择题 The writer of the article is()
单项选择题 In what way did the writer find the White family completely different from her own()
