Just now, I entered the website “Topic for Today”. I feel    1  (interest) in the report on middle school students’ using cell-phones on campus. In fact, more students now come to school  2  cell-phones. My schoolmates have different opinions. Some think   3  is convenient to get in touch with others with the cell-phone, which also makes you feel safe especially in time of trouble.  4  , it is nice to enjoy_____5__(variety)functions of different cell-phones.  6  think differently. First, the cell-phone is not   7  must in school, as  there are some IC phones there,  8    _(make) it easy to call others. Second, many students often play e-games and send e-massages with their cell-phones, even in class, 9 ___will surely have bad effects on their study. What’s more, it ___10_____(result) in a great waste of time and money. In my opinion, the cell-phone is a useful tool in our daily life. But it doesn’t mean we can use freely in school.

在一条远洋海轮因新鲜蔬菜不足，多数海员出现了牙龈出血现象，这是因为膳食中缺乏（    ）

A．维生素B

B．维生素C

C．维生素D

D．维生素A