What influence did foreign nations have on china from 1912-1938?

Influence started with the purchasing of tea from China, who was not involved in the world trade of the day. At that time Chinese were the only peoples into drinking tea, and would only sell it for gold to other nations.

The British East India Co started the production of tea in India. British government financial support of the East India Co, was the reason for the tea tax, that sparked the "Boston Tea Party".

China's attitude to the sail of tea for gold, caused both Briton & America financial problems, and to get back some of the gold spent for tea, was started the first drug war. Britain, and America used their warships, in what was caled "The China Station" to protect their merchant ships, shipping opium from Turkey, the only place opium grew naturally, to sell it for gold to the Chinese.

Funny thing! This opium war was responsible for the widening of the farming of the opium poppy. The opium products coming from Afghanistan to day, would not have happened, had the British & Americans not taken poppy seeds out of turkey!

Like most things, foreign trade has proved destructive, to both sides of the trade relationship eventually.