左心衰最早的临床表现是:()
A、劳力性呼吸困难
B、阵发性夜间呼吸困难
C、哮鸣音及吸气性呼吸困难
D、带有哮鸣音的呼气性呼吸困难
E、端坐呼吸
参考答案:B
_____ the fact that David failed in the competition, his teacher thought be had done his best. [ ]
A. Although
B. Despite
C. While
D. Without
小明的奶奶由于身体肥胖,因而常年吃素,可她并未因此而患夜盲症.这是因为( )
A.维生素A可由维生素B1转化而来
B.新鲜水果中含有维生素C
C.植物性食物中含有的胡萝卜素可以在人体内转化为维生素A
D.植物性食物中也含有维生素A