切西瓜时会流出许多汁液，汁液主要存在于细胞中的[ ]
A．液泡
B．细胞质
C．细胞膜
D．细胞核
答案：A
Ever since Daming graduated from the university, he _______ in the present company for 15 years and he is now chief engineer of the company.
A．worked
B．has been working
C．is working
D．works
Charcot三联征常提示的疾病是（）
A.肝脓肿
B.急性化脓性胆管炎
C.胆道蛔虫病
D.原发性肝癌
E.钩端螺旋体病
