Words similar to optional

Example sentences for: optional

How can you use “optional” in a sentence? Here are some example sentences to help you improve your vocabulary:

Obligation: Optional
A popular optional excursion is an hour’s detour to Guangzhou Zoo, founded in 1958.
The deconvolution calculation of the unknown input function I(t) is routinely described by the following three plots: 1) Plot of the calculated I(t) versus time, along with a comparison with the gamma distribution deconvolution (optional) and the model gamma distribution input (optional), 2) Comparison of the calculated deconvolution venous concentration with the experimental data, and 3) Plot of the total amount of absorption versus time.
This is optional, but if it is a memorial service, there will be no body to view.
Alternative Allowance Allocation for Units in Certain Utility Systems With Optional Baseline.