进行放射性核素通气功能显像患者的准备，下面哪种说法是不正确的（）。

A.患者取坐位

B.帮助患者学会正确呼吸以配合检查

C.采集后位图像

D.分别采集左肺野和右肺野

E.探头紧贴患者后背

An airplane manufacturing company routinely builds fighter jets for the U. S. armed forces. It takes fourteen months to build one jet, and the government pays for them in installments over the fourteen-month period. Which revenue recognition method should be used（）

A. Installment sales method.

B. Completed contract method.

C. Percentage-of-completion method.