He began to learn Chinese in his _____.A.fifty B.fiftieth C.fifties D.fifth
问题描述：
He began to learn Chinese in his _____.
A.fifty B.fiftieth C.fifties D.fifth
答
c
答
C in sb's +数词的复数形式，意思是在某人的某个年龄段
答
He began to learn Chinese in his _____.
选C
这是固定词组【in ones +年龄+s】表示在某人多少岁时,数字用复数
答
C