In column A I have sentences. In column B a list of keywords that I have named 'lookup'.

A B
1 John is a lawyer city FALSE
2 He works in the city box TRUE
3 The dog is old kitchen FALSE
4 My kitchen is a box TRUE

I have this formula --- =OR(ISNUMBER(SEARCH(lookup, A1))) --- with CSE. It returns True for line 2 with 'city' and line 4 with kitchen and box. What I want is the result to be the actually word it found and if there are two or three (or more) found to comma delimit them. So for line two it would put in the result 'city' and in line 4 'kitchen,box'.

I have searched high and low and maybe I am using the wrong formula? Please help.