Roger... No intent to offer offense, but your question lacks some info that might even let us guess at your experience level... so, starting from ground zero, because it sorta' looks as though you don't have the module installed:

1. Did you install Text::Sentence?
2. Whence? How?
3. Why is your instruction to use the module (ie, show us your code) as far down as line 10? (My shortsightedness on this may not reflect any problem on your part, but code will help).
4. Assuming the code will show that you included use strict; use warnings;, is the error message you posted the only response when you try to execute (or test compile) your script.

Finally, please read carefully and heed the instructions around the text-entry box where you entered your question (and where you can edit it, or which you'll see again when you respond to this request for clarification) about the use of <code>....CODE and DATA should be enclosed between code tags... </code> like this (or, <c> ...like this... </c>).

Construe "DATA" to mean error messages, warnings, and such like as well as the ordinary usage.

update: Found the missing "us" (my dog took it outside to play with) and restored to para 1