How to solve the final round of 2020 China National Linguistics Olympiad?
(This is a work in progress)

This question is a test of the ability to apply linguistics and Chinese character principles to solve the matching puzzle. I will assume the following, in order of most to least certain:

Four-character phrase patterns are religiously adhered to, due to a desire to keep textual rhythm;
The principles of Tangut character structure is roughly the same as Chinese character structure (mainly semantic and phonetic components);
&quot;Simple concepts&quot; are represented by &quot;Basic characters&quot;. This is the character/writing system equivalent of the idea of a Swadesh List.

Now, I'll present how I would solve the puzzle.

(7) and (12)
As four-character rhythms are the most important factor, I'll start off by matching the four-character correspondences between Tangut and Chinese.

Each one of these corresponds to one of

其徐如林
不動如山

The matching character in the Tangut fragment is the second character, which therefore corresponds to 「如」. If the second Tangut character corresponds to 「如」 while Chinese 「如」 is the third character, this implies that the Tangut's equivalent of 「如」 works in the opposite direction to the Chinese 「如」.

As an analogy, Chinese 「的」 or 「之」 works in the opposite direction of English of.

There is a reduplicated character in (7), while there is no such reduplication in either of the Chinese equivalents. This means that the Tangut reduplication corresponds to the use of a filler character in the Chinese to keep the four-character rhythm, and the only filler character in use in the Chinese phrases is 「其」. (7) therefore corresponds to 「其徐如林」, with the reduplication meaning something like 「徐」 - consider the Tangut reduplication to be something like 「慢慢」.
Thus,


 - (7) means 其徐如林
 - (12) means 不動如山

and

 - The first character in (7) has a semantic field of (many) plants, trees;
 - The first character in (12) has a semantic field of mountain.


(22)

If the first character in (12) has a semantic field of mountain and the only other phrase containing a character with a semantic field of mountain is 「峰」 (mountain peak) in 「峰雲」, then

 (22) matches to 「峰雲」.

and

 The second character in (22) is the Tangut equivalent of 「雲」.


Determination of the Tangut equivalent of 「氵」 (semantic component meaning water)

This is the character for cloud, and we can see that the left hand side component occurs in the following phrases:

「雲」 roughly has the following semantic fields:

Sky, weather, sun
Water

The Chinese phrases which may correspond to sky, weather, sun are:

白露
(maybe) 龍神
峰雲

The Chinese phrases which may correspond to water are:

唾液
魚
白露
峰雲
泥土
水門

so we can deduce that

 
 probably means water rather than sky, sun, weather.