It turns out that the less skilled pianist spends more time looking at her fingers than does the expert who, in contrast, is more likely to be looking at the sheet of music, or looking ahead at keys he's not yet playing.
事实证明,技术较差的钢琴家比专家花费更多时间看自己的手指,相比之下,专家更有可能看乐谱,或者提前看他尚未弹奏的琴键。
than 引导的比较从句,整个比较结构是"the less skilled pianist spends more time looking at her fingers than does the expert…"。从句采用倒装结构"does the expert"(助动词 does 提前),expert 后接非限制性定语从句"who…is more likely to be looking…"修饰。