题目

阅读理解 No poem should ever be discussed or “analyzed”，until it has been read aloud by someone，a teacher or a student．Better still，perhaps，is the practice of reading it twice，once at the beginning of the discussion and once at the end，so the sound of the poem is the last thing one hears of it． All discussions of poetry are，in fact，preparations for reading it aloud，and the reading of the poem is，finally，the most telling “interpretation” of it，suggesting tone，rhythm，and meaning all at once．Hearing a poet read the work in his or her own voice，on re如图，AB是⊙O的直径，CD是⊙O的弦，∠DAB=51°，则∠ACD=    ．