Complex sentence: But negative customer reaction in 1953 and early 1954 models caused sales to plummet Just 3640 of this model were built and nearly a third were unsold at year's end.
Split into simpler sentences: But negative customer reaction in 1953 and early 1954 models caused sales to plummet. In 1954, just 3640 of this model were built and nearly a third were unsold at year's end.