Show surprise at strange gaps (4)
I believe the answer is:
gasp
'show surprise' is the definition.
(I've seen this in another clue)
'strange gaps' is the wordplay.
'strange' is an anagram indicator.
'gaps' is an anagram of 'GASP'.
'at' acts as a link.
(Other definitions for gasp that I've seen before include "Utter breathlessly" , "Have trouble breathing" , "First Greek letter" , "Convulsive breath" , "Fight for breath" .)