问题：
Describe four types of standard.
答案：
Types of standard(i) A basic standard is a standard established for use over a long period from which a current standard can be developed,(ii) An ideal standard is one which can be attained under the most favourable conditions, with no allowance for normal losses, waste or idle time,(iii) An attainable standard is one which can be attained if a standard unit of work is carried out efficiently. Allowances are made for normal losses,(iv) A current standard is based on current levels of performance. Allowances are made for current levels of loss and idle time, etc.