declare和 announce 在语法上有什么区别？

announce 和declare 语义相近,中心意思是to bring to public notice(公之于众),但结构有区别
announce 后接名词或代词或that宾语从句，而declare除接上面结构以外还可接复合宾语等结构
declare 较为正式,在语义上还有些特殊的用法

试比较下列句型。
1.Soon Germany declared war on France.
不久德国对法宣战(不用 announce)
2.Announce a cease-fire
宣布停火
3.The bell announced the end of the class.
下课铃响了(不用declare)
4.The committee announced/declared the results of the experiment.
委员会宣布了实验的结果
5.She declared her intention to run for office
她宣布了要竞选官员的意愿