If not, add a tablespoon of olive oil, mix well, cover and leave to stand, stirring occasionally to prevent sticking.
Note: because it's kept hot and covered, pasta will continue cooking, so you should not keep it too long.
Remarks
It's quite surprising to see how many ways of preparing and serving pasta there are, and at the same time how great a simple pasta dish can be: a pan of spaghetti, a dash of olive oil, some grated Parmesan, what more do we need? hummm, oh yes, a good glass of Italian wine perhaps...