I find it very helpful to take some time (around 5-15 seconds) to think when I'm asked something. Mostly because my main issue is being too agitated to find the right words when confronted on the spot; waiting lets me calm down, which in turn helps me with formulating what I'm about to say. Plus I have more time to think about what to say.

Of course it's a bit tricky to pull off, and purportedly more so in English-speaking contexts: some studies [1] have shown that "anglophones tend to be most uncomfortable with long gaps in a discussion."

[1] https://www.bbc.com/worklife/article/20170718-the-subtle-pow...