下列说法正确的是[ ]
A.一般来说,各个民族都有自己的语言
B.英语最初是美国的民族语言
C.汉语的使用主要分布在中国和南亚等
D.使用人数最多的语言是英语
答案:A
细菌的某个基因发生了突变,导致该基因编码的蛋白质肽链中一个氨基酸替换成了另一个氨基酸。该突变发生在基因的[ ]
A.外显子
B.编码区
C.RNA聚合酶结合的位点
D.非编码区
________,I have never seen anyone who is as capable as David.[ ]
A.As I have traveled so much
B.As long as I have traveled much
C.Now that I have traveled much
D.Much as I have traveled