More and more high-rise buildings have been built in big cities _____ space.[ ]

A. in search of                    

B. in place of

C. for lack of                      

D. for fear of

以下哪种药是兴奋呼吸中枢的药物

A．尼可刹米

B．匹莫林

C．甲氯芬酯

D．咖啡因

E．哌甲酯