A:淹没无闻风帘翠幕残羹冷灸嬉笑怒骂
B:良辰好景白璧微暇礼上往来膏粱子弟
C:揭杆而起刎颈之交修养生息委曲求全
D:栩栩如生负荆请罪冥思苦想遐思迩想
—Which is your f____ subject?
—Art. It's fun.
下列方程是一元二次方程的是( )