1. The speech was interesting and instructive.
    报告很有意思，很有教育意义。

2. Let us compare them with adults learning a foreign language, for the comparison is both interesting and instructive.
    让我们来将儿童学习母语与成人学习外语来进行一下比较，因为这种比较不仅很有趣，而且很有教育意义。