缺铁性贫血患儿对感染的易感性高。最可能的机制为()
A.细胞免疫功能缺陷
B.微量元素缺乏
C.能量和蛋白质营养不良
D.体温较低
E.体液免疫功能缺陷
参考答案:A
— I'm sure Andrew will come out first in this gymnastic competition.
— I think so. He ________ for it for months. [ ]
A. is preparing
B. was preparing
C. had been preparing
D. has been preparing
旅游业、体育运动消费业、图书出版业及文化娱乐业为争夺消费者一年内的支出而相互竞争,它们彼此之间是()
A.愿望竞争者
B.属类竞争者
C.产品形式竞争者
D.品牌竞争者