translation.en: And, indeed, once again we're moving forward to the kind of sexual expression that we probably saw on the grasslands of Africa a million years ago, because this is the kind of sexual expression that we see in hunting and gathering societies today.
translation.zh: 的确，我们在性表达上再一次 回到了百万年前非洲大地上的情景 因为这就是以打猎和采摘为生活方式的 社会具有的性表达