A:硒元素有+6、+4、-2等常见化合价
B:SeO3的水化合物是一种含氧酸
C:H2Se的热稳定性比 H2S的稳定性强
D:Se的单质在常温下呈固态
Microsoft ended support for Windows XP after April 8, which _______a major operating system for some Chinese computer users, and advised users to upgrade to Windows 8.1.