The apostrophe for the pause may not be programmed as acceptable. Try cut and paste of the náhástʼ with the curved apostrophe. Yours should be accepted, I believe, but it's still a beta work in progress. I had an early lesson where this exact distinction had me stuck in place for a few minutes but cut and paste of the answer provided worked me through it, at the end where duo brings up the ones you didn't get right or "right". Hope that helps you.