Translation:This watch is very important to me.
"precisous" is not a word. Don't try and tell me I spelt precious wrong, because I didn't. https://en.oxforddictionaries.com/definition/precious.
Five long years, he hid this uncomfortable piece of metal the only place he could...
Because important（たいせつ）is an adjective. It is describing the noun - watch (うでとけい）and giving us information about it. Also "important thing" would be たいせつ な もの - important - adjective modifying thing - a noun. Even then the English still sounds odd - This watch is a very important thing/object to me. To convey the feeling of what you are trying to say in English I think you would say - This watch has sentimental value for me - or something like that.
The correct solution spells the word "precious" wrong, and writes it as "precisous", so I keep on getting the answer "wrong" and not getting through. Has anyone else had this problem, and if so, should I just use an alternative word? I reported the correct solution already, so hopefully Duolingo clears that up.