Answer:
In the world war 1, China was against Germany and had declared war on Germany in August. The reason for declaring the war was that China wanted to regain control over Shantung peninsula which was very important for it.
It wanted to regain power in that region before Japan could assert it's strength in that region. So China wanted to have more negotiable powers at the post war bargaining table so that it could have more power than Japan and get control over the peninsula.
