姑娘们一边采茶，一边愉快地唱歌。

As they picked tea, the girls sang happily.

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这个男孩一边走，一边愉快地唱歌。

As the boy walked, he sang merrily.

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这些男孩一边沿湖边走，一边愉快地唱歌。

As the boys walked along the lake, they sang happily.

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这些男孩一边沿湖边走，一边愉快地唱歌。

As the boys walked along the lake, they sang happily.

youdao