Once upon a year
We had a boy
Our boy
Boy

Once upon a day
It started raining
No complaining
Just rain

Once upon a park
We took a walk
And talked
And talked

Once upon a house
We lived awhile
Inside
In style

I couldn't believe it
I couldn't conceive it

Once upon a year
We had a boy
Our boy
Boy

Once upon a road
We took a drive
To the seaside
For an ocean drive

I couldn't believe it
I couldn't conceive it

What I was about to say
That was not an easy thing to play
What I was about to do
Was to let you know that we both love you

歌詞理解の手助けに：

1) Once upon a year:once upon a timeで昔々
2) complaining:不平・不満
3) took a walk:散歩をした
4) In style:派手に・上品に
5)
6)
7) seaside:海岸
8)
9) about to:〜しようとする
※独自解釈なので他の意見・間違い指摘など歓迎します