只能表示2个氢原子的化学符号是（  ）

某同学常出现面色苍白、头晕、疲乏、精神不振等症状，医生给他做了血常规化验，在显微镜下观察到的血涂片玻片标本的某个视野如图，化验结果如表，根据图表信息回答问题

短文填空，根据短文内容和首字母提示，把文中所缺词语补充出来，使短文完整、正确、通顺。（每空限填一词。）

     Nowadays, you can see many people busy on their smartphones(智能手机) if you look a____ Smartphones make our lives easier. But have you ever t ____  about what they mean to your eyes?

    Staring(盯) at smartphones for long time gives you dry eyes and even causes a disease c____ glaucoma(青光眼).

While you're probably not going to stop using your smartphone, there are a few things you can do to protect your eyes. Hold your phone at least 30 cm away from your eyes when using it. Take a break every h____  and try the following: look at something at least five meters away from you and then focus on the tip of your nose. Repeat this s____ times. It should reduce(减少) the discomfort in your eyes.

下列四组国家中，全部为我国陆上邻国的是 (    )

2014年3月28日，是西藏百万农奴解放55周年纪念日，当日，西藏各地群众以不同方式共同庆祝这一盛大节日，回答问题。