我觉得是B呢 A When an active tooth in the shark’s jaws is lost or worn down, many spare teeth lie in seemingly limitless reserve, each of which are ready to slide into the appropriate position. should use "is" E In the shark’s jaws, many spare teeth lie in seemingly limitless reserve, each one ready to slide into the appropriate position whenever an active tooth is lost or worn down. each,one重复, ready to前少了be动词 NN们指教 |