系统软件的核心是（）
A、操作系统
B、诊断程序
C、软件工具
D、语言处理程序
参考答案：A
With everything needed________, she went out of the shop, with her hands full of shopping bags. [ ]
A. bought
B. buy
C. to buy
D. buying
下列哪组药为百合固金汤和养阴清肺汤所共有（）
A.白芍、甘草
B.牡丹皮、当归
C.麦冬、贝母
D.生地黄、玄参
E.桔梗、薄荷
