The great theme was at Prescott's disposal. In order to feel sure-footed in the language, he went over his Spanish grammar again. Then he began to read all round the subject. Beginning with the general laws of nations, the constitutional history of England, the histories of the continental countries, France, Italy, Germany, Portugal, the general history of Spain, before he settled on his special field.请教一下专家老师，红色部分的句子结构是不是有问题啊？这是主句被简化了么？