Hi @LauliQwan, and welcome to the forums! 🙂
Can you post a link to the course?
In My Little Word Land, if words like this are separated by semicolons, then things should work as you've described 🙂 (Well, mostly. You'd be able to type "am", "are", or "is", but still not "am are")
Memrise used to have people separate words with commas, and then they switched to separating words with semicolons, which broke a lot of courses. I'm hoping to add a feature to My Little Word Land that will let people automatically fix this 🙂