Intuitively, mapping content words in sentences is more important than mapping non-content words.
step (3e) further weights sentence-level cosine similarity using the aligning ratio of content words in sentences, AlignedRatio cw, computed as 2×|CWo CWs|/(|CWo|+|CWs|) where the size of the common content words is divided by the sum of the size of the individual sentential contentword set.