那首

that song

→ 那
phrase Uncommon #11,573
that song 那 means “that,” and 首 is the measure word used for songs, poems, and other musical pieces. The noun can be omitted when it is clear from context.
CH: 你还记得那首歌吗?
EN: Do you still remember that song?

我记得在哪儿听到过那首音乐

I remember hearing that piece of music somewhere.

那首多么美

That piece of music is so beautiful.

— 蓝白红三部曲之蓝 (1993)

他们非常喜欢那首歌曲

They really like that song.

是的正是那首

Yes, that’s the one.

— 死亡诗社 (1989)

这不是刚才那首曲子

Isn't this the piece that was playing just now?

— 海上钢琴师 (1998)