Hey there my friend! In this sentence, I found that there were a few articles missing and a little bit of unnecessary repetition. Here is how I would reword it: Wearing a mask is just one out of countless preventative measures. In the above correction, you would establish a subject (a mask) and you would avoid repetition. Since you're already mentioning preventative measures in your sentence, there's no true need to say it twice. Thanks for all of your hard work! Learning the English language can be a little difficult. If you ever need any help mastering different topics like word order, articles, or verb tenses, be sure to reach out! I would be happy to help. You can check out my teaching profile here: https://www.italki.com/learnwithlj

Wearing a mask / masks is a preventive measure among countless preventive measures. Wearing a mask / masks is a preventive measure among countless others. Good sentence structure though :)

Wearing a mask is one of many preventative measures. Wearing a mask is one of countless preventative measures.

Hi, I would suggest adding 'a' or 'one' before the word preventive.