試題詳解

5. Tacos, bagels, and sushi, ________ at fast-food counters everywhere, were once available only in authentic ethnic restaurants. You had to order such food in Mexican cantinas, Jewish delicatessens, or Japanese seafood bars.
(A) can now be found
(B) those can now be found
(C) what can now be found
(D) which can now be found .