B

练习内容

[{"word":"back","pronun":"[b\u00e6k]","translation":"adv. \u56de\u539f\u5904; \u56de\u53bb adj. \u540e\u9762...","audio":"word_back_469bba0a_entry.mp3"},{"word":"bad","pronun":"[b\u00e6d]","translatio