你对句子结构的理解是错误的。注意主句的时态rose为一般过去时,as引导的是时间状语从句而不是原因状语从句。as从句的谓语动词为combined,to propel不定式短语作as从句的结果状语,而不是谓语。
Oil rose higher than $120 a barrel on Monday as increasing prices for fuels, such as petrol and diesel, combined with lingering concerns over supplies from Russia to propel crude to its highest level in two months.
as引导的原因状语从句中increasing prices做主语,谓语不应该是propel吗?为何此处用to propel?