选择题：The boy ______ . Spanish for six years by the time

题目内容：
The boy ______ . Spanish for six years by the time he takes his examination.
A、 has studies
B、 will have studied
C、 has been studying
D、 had studied
参考答案：

轨道水平的变化不能太急骤，在1m距离内变化不得超过A、 1mmB、 2mm

轨道水平的变化不能太急骤，在1m距离内变化不得超过A、 1mmB、 2mm C、 3mmD、 4mm

分类：石家庄铁道大学-大学英语3  题型：选择题
查看答案