My immediate reaction was one of shock.

我当即的反应是大吃一惊。

《牛津词典》

Your immediate reaction: fear!

你瞬间的反应：恐惧！

youdao

So what is my immediate reaction?

我的第一反应是什么？

youdao

The ego provides the immediate reaction to the events of reality.

VOA: special.2010.04.13

White House Press Secretary Robert Gibbs had no immediate reaction to the assessments Democrats received from the economists.

VOA: standard.2009.03.10

There was no immediate reaction from either the Iraqi or U.S.government to his charges.

VOA: standard.2009.09.15

There was no immediate reaction from the broadcasters in the Fox and ABC cases.

CNN: High court rules for broadcasters on TV 'indecency'

Immediate reaction to the announcement has generally been critical, with low level specs being the main complaint.

FORBES: Samsung Rushes Tab 3, But Getting Ready To Spoil Apple's Party

Social analytics enables one to release messages on the web and get an immediate reaction to them.

FORBES: The New Opportunity in Research