Mr Brown has two children.and Mary is second one.加the行不行（加在is后
问题描述：
Mr Brown has two children.and Mary is second one.加the行不行（加在is后
答
必须加the.
序数词修饰名词，序数词前必须加the,表特指。
答
应该是这样: Mr Brown has two children, and Mary is the second one.
答
原句不对,加the即可,意为Mary是上文中两个孩子的第二个,加the后指代明确...
答
Mary is second one . 不对。
应该是 Mary the second one，加the。