1 . 他把论文放在一个空白信封里。
He placed the paper________ ________ ________ ________ .
He placed the paper
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2 . After completing it, please return the form to us ________ (在提供的信封内). （根据汉语提示完成句子）
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3 . 当他看到雾从河里升起，柔软的云包围着山顶，他流下了眼泪。
When he saw the mists rising from the river and the soft clouds________ the mountain tops, he was reduced to tears.
When he saw the mists rising from the river and the soft clouds
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