point algebra

例句：

1. 1. The teacher pointed to the blackboard with her finger.
   老师用手指指着黑板。
2. 2. We need to point out the mistakes in the report.
   我们需要指出报告中的错误。
3. 3. He pointed at the map and said where we should go.
   他指着地图说我们应该去哪里。