1. She was already sick, vomiting black mucus.

结构解析：这是含有现在分词的复合句。

主句是：She was already sick，现在分词短语是vomiting black mucus。这个现在分词短语在这里做伴随状况状语。

（详细讲解：玛丽病了，病状况是吐出黑色黏液，因此判断为伴随状况状语。）

2. And he announced to the Scottish lords that for the proper government of the country it was necessary for Mary to have a husband.

（一）结构剖析

这是含有宾语从句的复合句。

主句是：he announced to the Scottish lords，宾语从句时由that引导出的 for the proper government of the country it was necessary for Mary to have a husband。

在主句中，the Scottish lords是做句子的间接宾语，宾语从句做直接宾语。

宾语从句中for the proper government of the country时介词短语作原因状语，it是做形式主语，to have a husband是动词不定式做真实主语，for Mary是做状语，表示对象。

（二）写作句型

It is necessary for sb to do something.（某人做某事有必要。）