Complex sentence: In July 2011, the group released the album's second single, "Glad You Came", which became their second number-one single, staying there for two weeks, and in the top ten of the chart for six weeks.
Split into simpler sentences: In July 2011, the group released the album's second single, "Glad You Came", which became their second number-one single. It was number one for two weeks, and stayed in the top ten of the chart for six weeks.