“正式的”的英语？

他们15岁就辍学了，几乎未接受过正式的写作训练。They had left school at fifteen and were quite untutored in writing.从某些方面来说，正式的开幕仪式只不过是走个形式。In some ways, the official opening is a formality.这两项协议之间不存在正式的关联。There is no formal linkage between the...