这里用decided还是deciding？

donzhtm

下面用括号里的动词怎么填空，才比较地道？
看题：
He won't go; he's quite ___(decide) about it. 。
I won't give up; I'm quite ____(decide) about my opinion.
上面都用decided. 句子可以翻译成：
He won't go; he's quite decided about it. 他绝不去，他对此事很坚定。
I won't give up; I'm quite decided about my opinion.我对我的意见很坚定，我不会放弃。

同样的：
-Is Fred going to take the job?
--He is still ______(undecide).
这里也用undecided.

undecided
un·decided  / ˌʌndiˈsaidid /
adjective
[not usually before noun]
1.  ~ (about sb / sth) |  ~ (as to sth)  not having made a decision about sb / sth
   未拿定主意；犹豫不决:
   I'm still undecided (about) who to vote for.
   我还拿不定主意投谁的票。
2. not having been decided
   尚未被确定；悬而未决:
   The venue for the World Cup remains undecided.
   世界杯的举办地点尚未确定。
⇨ compare decided
decided
de·cided  / diˈsaidid /
adjective
[only before noun]
   obvious and definite
   明显的；明白无误的；确实无疑的:
   His height was a decided advantage in the job.
   干这项工作,他的身高是明显优势。