1. We will speak about Afghanistan where we both have a considerable amount of troops stationed.
speak about 谈及
He has nothing to speak about that thing.
关于那件事他没有什么可说的 。
2. He also cautioned against engaging with China’s telecommunications giant Huawei to help develop 5G networks in Germany and elsewhere.
caution against 警示,警告,告诫
And when one of you falls down he falls for those behind him, a caution against the stumbling stone.
当你们中的一个人跌倒,他是为后面的人失足,使他们小心避开绊脚的石头 。