The word ”中国”.
As you can see,the ”Zhong” with the first tone and the “Guo” with the second tone in Mandarin combined as a word of “中国” means “China”.
If we say the words in different tones in Mandarin,it probably means:
There are 3*4=12 possibilities, each of which contains multiple other possibilities represented by different Chinese characters that have the same pronunciation.
So…the tones do matter.