脐静脉插管换血疗法应注意：（）

A、换血过程抽注速度要均匀，注射器内不能有空气

B、输入的血液不能加热

C、观察伤口的出血情况

D、观察生命体征及全身反应

E、换血前、中、后抽取血标本

It is not rare in ________ that people in ________ fifties are going to university for further education. [ ]

A. 90s; the  

B. the 90s; /

C. 90s; their  

D. the 90s; their