咖啡因的作用是：

A．小剂量减轻疲劳，振奋精神

B．舒张支气管平滑肌，且能利尿

C．较大剂量可间接兴奋延髓呼吸与血管运动中枢

D．中毒剂量兴奋脊髓

E．可直接兴奋心脏，扩张冠状血管

The computer software is old, _____ very out of date. [ ]

A. or rather

B. rather than

C. other than

D. more than