创新型国家是指将科技创新作为基本战略，能够通过大幅度高科技创新能力，形成日益强大的竞争优势的国家，其科技进步贡献率在( )以上。

A．50%
B．60%
C．70%
D．80%

When possible，what is the FIRST step in fighting an engine fuel-pump fire which results from a broken fuel line?（）

A.Secure all engine room doors，hatches，and vents

B.Close the fuel line valve

C.Check the spread of the fire with foam

D.Cast the barge off the wharf