Complex sentence: The lyricist, Hugh Martin, wrote words which referred to the soldiers fighting during World War II. Garland thought the song as written was too mean to sing to Margaret O'Brien, so he changed the lyrics.
Split into simpler sentences: The lyricist, Hugh Martin, wrote lyrics which referred to the soldiers fighting during World War Two. Judy Garland thought the song as written was too mean to sing to Margaret O'Brien, so he changed the lyrics.