Number + 国
国 (guó) means "country" or "nation" and can function as a classifier or bound morpheme when counting or referring to countries. It appears after a numeral to specify how many countries are being discussed. For example, 两国 means "two countries" or "both nations."
两国领导人在会上进行了友好交流。
liǎng guó lǐngdǎorén zài huì shàng jìnxíng le yǒuhǎo jiāoliú.
The leaders of the two countries had a friendly exchange at the meeting.
这两国之间的贸易额逐年增长。
zhè liǎng guó zhījiān de màoyì é zhúnián zēngzhǎng.
The trade volume between these two countries has been growing year by year.
两国决定加强在科技领域的合作。
liǎng guó juédìng jiāqiáng zài kējì lǐngyù de hézuò.
The two countries decided to strengthen cooperation in the field of science and technology.