That's "Pigs on the Wing" (Part 2)

Try:

"Sing a song that can't be sung"

That's "Remember A Day".

How about: "is your conscience at rest"

...when it's put to the test...
Childhood's End


How about
"Marmalade, I like Marmalade" (spoken)

Alan's Psychedelic Breakfast

How about this one:
"He wore a scarlet tunic"

The Gnome of course

"ice cream taste good in afternoon"

Candy And A Current Bun

"Occasionally you showed a smile but what was the need "

Summer '68

how about
"isn't it sad we're insane..."

Point Me At The Sky

"Aye an' a bit of Mackeral settler rack and ruin"

Several Species Of... Ah, you know how it goes!

How 'bout:
"he can have the words"

Wearing The inside Out (my fave floyd song)

"The leaves are heavy around your feet"