托福阅读这一题的b选项有什么问题?
1个回答

选项They changed the direction of their flight at a rate of 15degrees per hour

是说小鸟以每小时15度角的速率改变方向.

而文中提到When the real Sun was visible,however,the birds

maintained a constant direction as it moved across the sky.

constant direction保持恒定的方向,说明小鸟的方向是不变的(在真的太阳可见的情况之下)