右图是某遗传病的家谱图。3号和4号为异卵双生。他们基因型相同的概率是()
A.5/9
B.1/9
C.4/9
D.5/16
参考答案:A
胃肠道手术,术前禁食的主要目的是()
A.避免手术困难
B.避免手术后腹胀
C.预防麻醉中呕吐造成窒息
D.防止术后吻合口瘘
E.早期恢复肠蠕动
Simon always __________ after school.[ ]
A. plays a football
B. play football
C. plays the football
D. plays football