题干
Mary is sad. Her dress is old. Mum gives her a new dress, she is happy now.
____ ____; ____ ____
答案(点此获取答案解析）
sad,happy,old,new
Mary is sad. Her dress is old. Mum gives her a new dress, she is happy now.
____ ____; ____ ____
成等比数列，
是
与
的等差中项，
是
的等差中项，则
（ ）