Mr. Lighthizer, who is leading the talks, had told him there had been no progress on the “structural” changes that the administration sought from China.

【翻译】主持此次会谈的莱特西泽曾告诉他，政府希望从中国寻求的“结构性”改革没有取得任何进展。

【分析】

Mr. Lighthizer（主语）, who is leading the talks（定语从句）, had told （谓语动词）him （间接宾语）there had been no progress on the “structural” changes （直接宾语）that the administration sought from China.（changes 的定语从句）