降低茶碱消除的因素是

A．咖啡因

B．流感疫苗接种

C．肝硬化

D．老年

E．异丙肾上腺素

You can only be sure of __________ you have at present; you cannot be sure of something __________ you might get in the future.

A．that; what

B．what; /

C．which; that

D．/; that