若地面信息处理插件软件由于未升级则不匹配时，则可能导致文件用IC卡转储不下来。
参考答案：对
已知学生选课信息表：sc(sno，cno，grade)。查询“至少选修了一门课程，但没有学习成绩的学生学号和课程号”的SQL语句是( )。
A．SELECT sno，cno FROM sc WHERE grade=NULL
B．SELECT sno，cno FROM sc WHERE grade IS"
C．SELECT sno，cno FROM sc WHERE grade IS NULL
D．SELECT sno，cno FROM sc WHERE grade=''
_____ these experiments were successfully completed would we think of
going into humans.
A．If only
B．So that
C．Only if
D．Even if
