Fridge【bīng xiāng】：Chinese pronunciation and writing

The Chinese pronunciation has 4 tones ¯ˊˇˋ, which are labelled above [i, u, o, a, o, e], for example, ā á ă à, ¯ 1, ˊ2, ˇ3, ˋ4, and in addition to the ¯ˊˇˋ symbols, 1234 can also be used to indicate the rhyme.
In addition to the ¯ ˊ ˇ ˋ symbols, it is also possible to use 1234 to indicate a rhyme, and to use a number at the end of a spelling.
In books with pinyin, the rhymes ¯ˊˇ¯ are usually used; for messages using spelling, numbers are sufficient.
Each word is spelled with only one rhyme. If there are two or more words in the same meaning, the spelling is still based on one word, one rhyme, and one set of spelling.
Examples: (Learning)
Learning　学习，【xué xí】xuéxí ，【xue2 xi2】 xue2xi2
Practice　练习， 【liàn xí】liànxí，【lian4 xi2】 lian4xi2
with spaces between the pinyin of the words and without spaces between them，Both representations are fine．