I don't like stories _______ have unhappy endings.
A:who
B:that
C:where
D:those
中东地区的主要人种为( )
Little Tom sat watching the monkey dancing in front of him, ______.
人体缺乏必需的元素易患疾病,下列说法正确的是____
A、缺铁易引起贫血
B、缺氟会引起甲状腺肿大
C、碘元素摄入量不足易患骨质疏松症
D、青少年预防佝偻病,应适量补____.