A vacant lot or a bombsite can, to the amateur naturalist, produce an extraordinary variety of flora and fauna. 对于业余博物学者来说，在一片空地上或被炸后的废墟里可能发现种类繁多的植物群和动物群。
He retired in 1970, on his fiftieth birthday.他在1970年自己50岁生日时退了休。A golden wedding is the fiftieth anniversary of a marriage.金婚是结婚五十周年纪念日.Dartmouth College just marked the fiftieth anniversary of that summer study.在那个夏季研究上...
The stewards all wore armbands.乘务员都戴了臂章。Organisers had consulted widely with police, stewards and safety officers to ensure tight security.组织者广泛征询了警方、管事和保安的意见，以保证绝对安全。The stewards' badges are made so they do not uns...