我国现存最早的石塔是( )。
A．妙应寺白塔B．登封嵩岳寺塔C．神通寺四门塔D．北京天宁塔
参考答案：C
—Where is our English teacher?
—She is in the classroom, ________ the exercises _________ the students have done at home.
A．explaining; /
B．explaining; for
C．explained; to
D．explained; from
在Visual FoxPro中，主关键字的值不能为 【6】 。
