1.They went surfing and s___ and felt robots.
2.Han Meimei went to school on foot yesterday.
（用适当的单词或词组替换句子中的画线部分,句意不变）
（画线部分：went to on foot) （ ）
3.There is a very high hill in the village.
（用适当的单词或词组替换句子中的画线部分,句意不变）
（画线部分：very high hill) ( )