这是两个独立的句子。分号前面一句,分号后面另一句。
第一句
主语:Our part-Indian guide;
谓语:had cleared ;
宾语:the path to the lake ;
状语:the day before;
第二句:
主语:we
谓语:saw
宾语从句:where he had impaled the lopped head of a boa, open-mouthed, on a pointed stick by the canoes, for decoration.
状语:when we walked the path (时间);
从句中的主语:he;
从句中的谓语:had impaled;
从句中的宾语:the lopped head of a boa;
从句中的状语:on a pointed stick by the canoes(地点);for decoration(目的);
补语:open-mouthed,进一步描述lopped head of a boa。