导致尿路感染最常见的致病菌是
A．沙雷杆菌
B．变形杆菌
C．金黄色葡萄球菌
D．大肠杆菌
E．粪链球菌
参考答案：D
She had almost failed the exam, but her sister, ________had done very well.[ ]
A. contrast with
B. contrasting with
C. by contrast
D. by difference
渗透压
