Sentence:  Only the memory of previous hurt , bewilderment and perplexity made him sure that if he did not ask B ' dikkat when he , Mercer , was happy , the answer would no longer <WSD>be</WSD> available when he needed it . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)