To answer the first part of your question, I'd like to say that our studies were very extensive.
你问题的第一部分,我要说的就是我们的研究非常广泛。
This person recognized the words for river and guitar, and so Haley thought that his ancestor must have come from Gambia.
这个人认出了表示“江”和“吉他”的这两个词,于是哈利就认为他的祖先准是来自冈比亚。