Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Let me give you an example: In 1582 the united provinces invited francis, duke of anjou to lead them; but after a failed attempt to take antwerp in 1583, the duke left the netherlands again. after the assassination of william of orange (10 july 1584), both henry iii of france and elizabeth i of england declined the offer of sovereignty. however, the latter agreed to turn the united provinces into a protectorate of england (treaty of nonsuch, 1585), and sent the earl of leicester as governor-general. this was unsuccessful and in 1588 the provinces became a confederacy. the union of utrecht is regarded as the foundation of the republic of the seven united provinces, which was not recognized by the spanish empire until the peace of westphalia in 1648.
The answer to this example can be: In what year did francis, duke of anjou leave the netherlands?
Here is why: The generated question is perfect. Because the question is based on second sentence of the input passage and its answer is 1583.

OK. solve this:
On 28 January the PPS and the Social Democracy of the Kingdom of Poland and Lithuania called for a general strike; over 400,000 workers became involved in strikes all over Poland, a strike that lasted for four weeks. This was only a prelude to an even larger series of strikes that rocked Poland over next year. In the years 1905-1906 close to 7,000 strikes and other work stoppages occurred, involving 1,3 million Poles. Protesters demanded both improved conditions for workers and more political freedom for the Poles. By February, students at Polish universities had joined the demonstrations, protesting russification and demanding the right to study in Polish language. They were joined by high school students and even some from the elementary schools. While the Russian government gave in and agreed to some concessions towards the Polish nationalist movement , many - particularly the workers - were still unsatisfied. In some places in Poland, the school strikes lasted for close to three years. Major demonstrations occurred on May 1 , and about 30 people were shot during a demonstration in Warsaw. Later that month, for a time, public order disintegrated in Warsaw during a spontaneous campaign against the criminal elements as well as Russian collaborators.
Answer:
What two countries were there strikes in?