Many young people don't work hard, and regret it later when the opportunity is gone.They only realize it________it is too late.

A．when　

B．before

C．in case　

D．until

从覆盖范围上看，幼儿园计划分为（）

A.长期计划、中期计划和短期计划

B.常规性计划和临时性计划

C.固定计划和派生计划

D.全园工雏量f划、各部门工作计划和个人计划