Just put a page with a question between each trial that says something like "Preparing next trial" and auto advances after a few seconds.
Hello
@daweibai ,
If you have one question on each page then you can use timer question in every page and auto advance after two seconds.
You can un-check show timer option so the respondent cannot see the timer
Also, Question randomization will disable any page breaks you have set up, and so are not recommended for use with timing questions. Page breaks set in the Look & Feel also do not work well with timing questions.
Please follow this page for using
timer question
OR
You can put js(onready) in each question:
`setTimeout(function () {jQuery('#NextButton').click();},2000);`
OR
If you have auto-advance feature in every page(i.e from first question to last) then you can also paste the above code in look and feel -> advanced -> header(edit)-> html view in script tag