Complex sentence: The M6 motorway runs from junction 19 of the M1 in Catthorpe, near Rugby via Birmingham then heading north passing Manchester, Preston, Carlisle terminating at Gretna, where it joins the A74 (M) at the Scottish border which continues to Glasgow.
Split into simpler sentences: The M6 motorway runs from junction 19 of the M1 in Catthorpe, near Rugby via Birmingham then heads north, passing Manchester, Preston, Carlisle and terminating at Gretna. Here, at the Scottish border it joins the A74 (M) which continues to Glasgow.