2008-08-27 問題2.53 SICP (list 'a 'b 'c) ;(a b c) (list (list 'george)) ;((george)) (cdr '((x1 x2) (y1 y2))) ;((y1 y2)) (cadr '((x1 x2) (y1 y2))) ;((y1 y2)) (pair? (car '(a short list))) ;#f (memq 'red '((red shoes) (blue socks))) ;#f (memq 'red '(red shoes blue socks)) ;(red shoes blue socks)