twenty ， thirty ， ninety 等以﹣ ty 结尾的基数词变为序数词，是将词尾的字母-y改为﹣ i ，再加-th。th 四加起，八减 t ，九去 e ，“ ve ”要由-f替，five ， twelve 是两兄弟。
The little sheep _ now. 3. She always _ in the evening. 4. Sometimes I _ on the playground. 5. Talk quietly!
