Complex sentence: In late 1968, Gaye's recording of "I Heard It Through the Grapevine" became Gaye's first to reach number one on the Billboard Hot 100; it also reached the top of the charts in other countries, selling over four million copies.
Split into simpler sentences: In late 1968, Gaye's recording of "I Heard It Through the Grapevine" became Gaye's first to reach number one on the Billboard Hot 100. It also reached the top of the charts in other countries, selling over four million copies.