سوال ۱۲ کنکور ارشد علوم کامپیوتر ۱۴۰۳

Passage 1

People rarely notice it, but theoretical concepts can take decades to be assimilated into the mainstream of computing — yet when they are assimilated, they can have a profound practical impact. The stored-program computer, a concept central to computer science, owes its origins to Alan Turing, who studied the fundamental nature of computation in the 1930's. The practice of programming computers was significantly advanced by the development of the theory of automata and languages by Chomsky and others in the 1950's. Building on the foundations of context-free grammars, Knuth and others introduced algorithms and data structures for the efficient parsing of high-level languages, leading to tools such as YACC and enabling the software revolution of the 1960's. In the 1970's, theoreticians exploring the intrinsic complexity of computational problems identified the large class of NP-complete problems. They also demonstrated the utility of mathematical logic and automata theory for the verification of complex computer systems — for example, model-checking technology, now widely used by hardware vendors — and discovered the hard problems underpinning modern computer-security systems, notably the RSA public-key cryptosystem.

The word "they" (in "when they are assimilated") refers to ______.