第 1 题 · 六级
He came in panting after running up the steps, which his worried sister asked about at once.
核心词：pant pænt v. 气喘
他跑上台阶后气喘吁吁地走进来，忧心的妹妹立刻询问。
一般过去时主谓 + 现在分词作状语 + 介词短语 + which 从句 + at once短语 pant for breath短语 come in panting
He came in ___ after running up the steps, which his worried sister asked about at once.
第 2 题 · 六级
The baker added yeast to make the bread rise, which the old recipe has required for a century.
核心词：yeast jiːst n. 酵母
面包师加了酵母让面包发起来，这份老配方一百年来一直要求这么做。
现在完成时主谓宾 + 目的不定式 + which 从句（现在完成 + 时段）短语 add yeast短语 dried yeast
The baker added ___ to make the bread rise, which the old recipe has required for a century.
第 3 题 · 六级
The discovery gave fresh impetus to the research, which the young scientists have pushed forward with great energy.
核心词：impetus ˈɪmpɪtəs n. 推动力，促进
这一发现为研究注入了新动力，年轻科学家们充满干劲地推进。
现在完成时主谓宾 + 介词短语 + which 从句（现在完成 + push forward）短语 give impetus to短语 fresh impetus
The discovery gave fresh ___ to the research, which the young scientists have pushed forward with great energy.
