【简答题】写出下列溶液的质子条件式。 ①浓度为c mol.l-1(NH4)2HPO4;②浓度为c mol.L-1NaNO3
【单选题】下面关于passwd命令说法不正确的是()?
A.
普通用户可以用passwd命令修改自己的密码
B.
超级用户可以用passwd命令修改自己和其他用户的密码
C.
普通用户不可以用passwd命令修改其他用户的密码
D.
普通用户可以用passwd命令修改自己和其他用户的密码
【单选题】The appearance of distance learning produces a big effect on the society and leads to the revolution of a whole age.
【单选题】By making learning possible anytime and anywhere, distance education is a powerful tool _________ supporting lifelong learning.
【单选题】Sometimes online distance learning can be a problem because ______.
A.
it is not as interesting as face-to-face learning
B.
the learners only have the written text
C.
some students don't know how to organize their time
D.
some learners don't need face-to-face cues
【多选题】3G的主流应用技术标准( )P百度百科3G的解释
【单选题】Sometimes online distance learning can be a problem because _________ .
A.
learners can’t afford it
B.
learners get too many hints
C.
it involves excessive writing
D.
it is not available at the weekend
【简答题】According to the passage , distance learning is baBy almost any measure , there is a boom in Internet-based instruction . In just a few years , 34 percent of American universities have begun offering ...