阿里巴巴是亚太地区最大的网络零售商圈。

下列有关软件的叙述正确的是（）。

A.软件是指常见的应用软件

B.操作系统不是软件

C.软件是指贮存在软磁盘上的文件

D.软件是在硬件基础上对计算机功能的扩充和完善

―How are things going?

―The disabled _______ no relatives in Guangzhou _______ by the volunteers, who will graduate from Zhongshan University next year.

A．with; are taking care of

B．have; will be taken care of

C．with; are being taken care of

D．have; are being taken care of

应激性溃疡突出的症状是

A．上腹剧痛
B．反酸嗳气
C．心窝部烧灼感
D．突然发生上消化道出血或穿孔
E．频繁恶心呕吐

20世纪前半期发挥巨大作用的两大超级能量分别是核能的释放和航天事业。