Announcement

[Xinfu]

Could I use piece of?

-I have a __ announcement to make.

[Rusty]

You may, but only if 'of' is followed by an article.
That would mean that you have an announcement to make, but not in its entirety.

If you meant something else, you can't use 'piece of an/the'.

[Xinfu]

Excellent answer. Thank you.

[MWoll]

Rusty is correct here.

"piece of" does not always require an article, though.

"Can I have a piece of pie?" -- you say this if you are referring to pie on the table.
"Can I have a piece of the pie?" -- same thing.
"Can I have a piece of a pie?" -- they will say, "Which pie?"

[Xinfu]

Excellent answer. Thank you.