瞬发能反制。faq里面明确说的
Can I counterspell a quickened spell? What if I use the Reactive Counterspell feat (Player’s Guide to Faerûn, page 42)?
Yes. A quickened spell isn’t any more difficult to identify than a normal spell, despite its reduced casting time. As long as you’ve readied an action to counterspell (or you have the Reactive Counterspell feat, which allows you to counterspell without having readied an action), you can counterspell a quickened spell as normal.