传记作者的挑战在于既要成为侦探，又要成为诗人。
The biographer's challenge is to be both a detective and a poet.
Technology must serve society, not the other way around.
乳制品行业必须适应消费者偏好的变化。
解释：要量力而行，实力达得到就进攻，达不到就撤退。