Since I had and you had, are both unit vectors projecting I hat onto the line, passing through you hat.

因为我和你都是 都是单位向量投影到直线上 穿过你。

Focus in on what it does to one particular vector, and think about the span of that vector, the line passing through its origin and its tip.

关注它对一个特定向量的作用 考虑这个向量张成的空间 穿过原点和顶点的直线。

However, in the unlucky case, where your two original vectors happen to line up, the tip of the resulting vector is limited to just this single line passing through the origin.

然而 在不幸的情况下 当你的两个原始向量恰好对齐时 结果向量的尖端仅限于这条穿过原点的直线。