a painting on the wall 墙上的一幅画；在...旁, 靠近
the inn on the road 路旁的旅店
the town on the river 临河的城镇；向着...
march on London 向伦敦前进
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smile on sb. 对着某人笑；在...时候; ...之后立即
on the morning of May 5th 在五月五日早晨
on arriving home 刚到家就...
on analysis 经分析后；根据; 凭; 靠
