引起脓胸最多见的病原体是
A．金黄色葡萄球菌B．肺炎链球菌C．大肠埃希菌D．B群链球菌E．草绿色链球菌
参考答案：A
The father has been ____ for many years in order that his only son can be ____ with higher education. [ ]
A. fighting; served
B. struggling; equipped
C. working; offered
D. laboring; received
可使药物的亲水性增加的基团是()
A．硫原子
B．羟基
C．酯基
D．脂环
E．卤素
