腺苷脱胺酶基因突变可导致
A.苯丙酮尿症B.重症联合免疫缺陷症C.无丙种球蛋白血症D.Down综合征E.慢性髓细胞白血病
参考答案:B
— a year does your school have sports meetings?
—Twice a year.
A.How often
B.How soon
C.How long
D.How many times
在雅典,全体成年男性公民可以参加___________决定重大问题,他们在行政和__________中也发挥着重要作用。