Question：Why must planning materiality be reviewed throughout the audit?
　　A. Auditing standards so prescribe.
　　B. External factors may change the inherent and control risk assessments.
　　C. Mistakes discovered during the audit will affect materiality.
　　D. It is usually calculated by an audit junior.
　　E. Draft accounts may be altered.
　　The correct answers are: Draft accounts may be altered; External factors may change the inherent and control risk assessments; Mistakes discovered during the audit will affect materiality.
　　解析：The last point and the first one mentioned are connected - materiality is affected if mistakes are adjusted or if they are not. Audit juniors do not usually calculate planning materiality - this should be done by an audit senior or above, but even if they did, their lack of seniority is not the reason for the reappraisal. It is inherent in auditing standards that planning materiality will be reappraised during the audit, but the prescriptive guidance does not set out that auditors must do so.