Given the task definition and input, reply with output. This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: During the First Sino-Japanese War in 1894, Japan absorbed Taiwan. As a result of the Russo-Japanese War in 1905, Japan took part of Sakhalin Island from Russia. Korea was annexed in 1910. During World War I, Japan took German-leased territories in China's Shandong Province, as well as the Mariana, Caroline, and Marshall Islands. In 1918, Japan occupied parts of far eastern Russia and parts of eastern Siberia as a participant in the Siberian Intervention. In 1931 Japan conquered Manchuria from China. During the Second Sino-Japanese War in 1937, Japan's military invaded central China and by the end of the Pacific War, Japan had conquered much of the Far East, including Hong Kong, Vietnam, Cambodia, Myanmar, the Philippines, Indonesia, part of New Guinea and some islands of the Pacific Ocean. Japan also invaded Thailand, pressuring the country into a Thai/Japanese alliance. Its colonial ambitions were ended by the victory of the United States in the Second World War and the following treaties which remanded those territories to American administration or their original owners.
When was the last Sino-Japanese War?