* "Her enthusiasm for the project was infectious, inspiring everyone to work harder." (This uses "enthusiasm" as a noun.)
* "He approached the challenge with such enthusiasm that it was impossible to doubt his success." (This uses "enthusiasm" as a noun.)
* "The children were enthusiastically playing tag in the park." (This uses "enthusiastically" as an adverb.)
* "She spoke enthusiastically about her trip to Italy, her eyes sparkling with excitement." (This uses "enthusiastically" as an adverb.)
You can also use "enthusiasm" as an adjective:
* "The team had an enthusiastic response to the new coach's training plan."
Remember that the best way to use "enthusiasm" in a sentence depends on the specific context and what you want to convey.