Step 1 自主学习Introduction和Reading部分的语言要点，标出你认为的重点和疑难部分
1. 介词in, on, to, across, off, between在表示“某地与另一地相对位置”的句子中的运用。
1) in: (表地点和位置)在…之中；在…之内
Liaocheng lies in the west of Shandong Province.
Some islands in the India Ocean were completely destroyed in the tsunami.
2) on: （表地点）接近或靠近某地或表示在海、河等的沿岸。
We saw a house on the main road in the distance.
Weihai and Yantai are both cities on the west coast of the Bohai Sea.
