在科学预测今后可能发生偏差的基础上，在偏差实际发生以前，就采取措施加以控制，防止偏差发生的方法是（）。

A.正反馈控制

B.负反馈控制

C.反馈控制

D.前馈控制

Upon completing a project schedule, Roberta finds the critical path indicates the project will complete on April 15. As she works through the schedule, she finds there are several tasks with float. Task B has 10 days of free float, while Task F has 5 days of total float. If the start of Task B is delays, what is the completion date of the project

A．April 25.

B．Not enough information provided to calculat

C．April 20.

D．April 10.