How to use the "mom" '.FT' macro with a period?

[Steve Ross]

Groffers,
Following is the content of a "mom"-formatted file that poses a question to you.

--- begin ---This is Roman font.
.br
This is a sentence ending with a word in the italic font
(by using in-line escape sequences)
before ending with a Roman font \fIperiod\fP.
.br
When using the "mom" macro of `.FT' instead of escape sequences,
I would like to end a sentence with a Roman font
.FT I
period
.FT R
.br
How would I do that?
My problem is that I cannot start the next text line with the period
that ends the sentence because "groff" would interpret that as a control 
linewith a command rather than a period.--- end ---

Thanks for any help,
-- Steve