Don't know why(不知道为什么) Don't know why(不知为何) Don't Know Why(不知为何) 10.Don't know why(不知为何) Don't Know Why(不知为何); Don't ask me why(不要问我为什么) Don't know much(知道的不多) Don't know much (无须知道太多) Don't know why Don't know much(不太了解)