Question: "We've Only Just Begun" is a hit single by Carpenters written by Roger Nichols (music), and Paul Williams, an American composer, singer, songwriter and actor, wrote which part of the single?

Context articles: Someday Man
Murray MacLeod
We've Only Just Begun
Paul Williams (songwriter)
Conrad Reeder
Out in the Country
I Won't Last a Day Without You
Let Me Be the One (The Carpenters song)
Steve Stanley
Roger Nichols (songwriter)

Someday Man is the debut studio album by Paul Williams, released in 1970.
 Notable songs from the album include "Someday Man", "Trust" and "To Put Up with You".
 The song "Someday Man", written by Paul Williams and Roger Nichols, was first released by The Monkees (and sung by Davy Jones) on their 1969 single "Listen to the Band / Someday Man".
 Chuck Kaye was credited for direction.
Murray MacLeod (born September 9, 1940) is an American actor, television and film composer, and singer who, along with his sister, Melinda, and Roger Nichols, formed the Small Circle of Friends (Roger Nichols Trio).
 Simultaneously, he was a singer with The Parade (along with Jerry Riopelle and Smokey Roberds), that had a "Billboard" Top 20 hit, "Sunshine Girl" in 1967.
"We've Only Just Begun" is a hit single by Carpenters written by Roger Nichols (music) and Paul Williams (lyrics).
 Ranked at No. 405 on "Rolling Stone" magazine's list of "The 500 Greatest Songs of All Time", it is frequently used as a wedding song.
Paul Hamilton Williams, Jr. (born September 19, 1940) is an American composer, singer, songwriter and actor.
 He is perhaps best known for writing popular songs performed by a number of acts in the 1970s, including Three Dog Night's "An Old Fashioned Love Song" and "Out in the Country", Helen Reddy's "You and Me Against the World", David Bowie's "Fill Your Heart", and the Carpenters' "We've Only Just Begun" and "Rainy Days and Mondays", as well as for his contributions to films, such as writing the lyrics to the #1 chart-topping "Evergreen", the love theme from "A Star Is Born", starring Barbra Streisand, for which he won a Grammy for Song of the Year and an Academy Award for Best Original Song; and "Rainbow Connection" from "The Muppet Movie".
 He also wrote the lyrics to the opening theme for "The Love Boat", with music previously composed by Charles Fox, which was originally sung by Jack Jones and, later, by Dionne Warwick.
Conrad Reeder (also known as Connie Reeder Nichols) is an American singer, songwriter, writer and college professor.
 She was married to the late producer and recording engineer Roger Nichols for over thirty years.
"Out in the Country" is a song written by Paul Williams and Roger Nichols and performed by Three Dog Night.
 The song was produced by Richard Podolor, and was featured on their 1970 album, "It Ain't Easy".
 In the US, "Out in the Country" peaked at number 11 on the US adult contemporary chart, and number 15 on the "Billboard" chart in 1970.
 Outside the US, "Out in the Country" reached number 9 in Canada,
"I Won't Last a Day Without You" is a song with lyrics written by Paul Williams and music composed by Roger Nichols.
 It became a hit single for the Carpenters in 1974, reaching number eleven on the "Billboard" Hot 100 chart and number one on the easy listening chart.
 It was the Carpenters' ninth number one on the easy listening chart.
"Let Me Be the One" is a song written in 1971 by Roger Nichols and Paul Williams.
 It first appeared on the 1971 album "Carpenters" by The Carpenters.
Steve Stanley (born 1970) is an American music historian, reissue producer, and the founder of Now Sounds, a reissue record label established in 2007 and distributed by Cherry Red Records.
 Steve has produced reissues of albums by The Association, Janis Ian, The Cowsills, The Mamas & The Papas, The Knack, Ruthann Friedman, Donna Loren, Roger Nichols, Paul Williams, and Tiny Tim, among others.
 Prior to establishing Now Sounds, Stanley was hired by Bob Keane and co-produced reissues for Del-Fi Records.
 He later produced over 50 titles for Rev-Ola Records.
Roger Nichols (born in Missoula, Montana), is an American composer and songwriter.
 He is a multi-instrumentalist who plays violin, guitar, bass, and piano.