Put the Verbs in the brackets in the correct forms

1. For many years scientists (to study) the nucleus before they found that it is possible to split it.
2. Many power stations (to use) atomic energy for a long time before I knew it.
3. All this period scientists and engineers (to develop) rocket technology and electronics in close cooperation.
4. We widely (to use) electronic devices in industry for many years.
5. We know that our astronomers (to observe) the moon for a long time.
6. My friend (to make) these experiments to compare the weight of elements since the first of September
7. The question about the new experiment on this subject (to discuss) for some time before we came to a definite conclusion.
8. The fact that atom has a nucleus in its center, which is positively charged, (to discuss) by Ernest Rutherford in 1911.

November 7 marks 100 years since the Great October Revolution, which changed the course of Russian history. The revolution swept across the country, and in every city there is a chronicle of these days. The historian and local historian Airat Faizrakhmanov told ProKazan where and how the October Revolution took place in Kazan. In the early 20th century Kazan was the center of the largest military district with a 40,000-strong garrison. By the autumn of 1917, more and more citizens were dissatisfied with Russia's participation in the First World War, the soldiers did not want to fight and supported the Bolsheviks with the slogan "Down with the War"

In mid-October 1917 in Kazan, there was a wave of soldiers' rallies and meetings with the demands for an end to the war and the transfer of power to the Soviets. One of them, for example, was in the meadows behind the railway station. The Bolsheviks were headed by Karl Grassis in Kazan, but Nikolai Ershov became the recognized leader of the soldiers' mass.
On October 22, a general assembly was held in Kazan, where a resolution was passed on the transfer of power to the Soviets. On October 23, the Kazan Soviet of Workers 'and Soldiers' Deputies demanded that part of the soldiers be dismissed at home, sluggish clashes began in the city. In turn, on the night of October 24, the commissioner of the interim government, Kalinin, ordered the arrest of activists. Grasis was detained, Ershov managed to escape.

November 7 marks 100 years since the Great October Revolution, which changed the course of Russian history. The revolution swept across the country, and in every city there is a chronicle of these days. The historian and local historian Airat Faizrakhmanov told ProKazan where and how the October Revolution took place in Kazan. In the early 20th century Kazan was the center of the largest military district with a 40,000-strong garrison. By the autumn of 1917, more and more citizens were dissatisfied with Russia's participation in the First World War, the soldiers did not want to fight and supported the Bolsheviks with the slogan "Down with the War"

In mid-October 1917 in Kazan, there was a wave of soldiers' rallies and meetings with the demands for an end to the war and the transfer of power to the Soviets. One of them, for example, was in the meadows behind the railway station. The Bolsheviks were headed by Karl Grassis in Kazan, but Nikolai Ershov became the recognized leader of the soldiers' mass.
On October 22, a general assembly was held in Kazan, where a resolution was passed on the transfer of power to the Soviets. On October 23, the Kazan Soviet of Workers 'and Soldiers' Deputies demanded that part of the soldiers be dismissed at home, sluggish clashes began in the city. In turn, on the night of October 24, the commissioner of the interim government, Kalinin, ordered the arrest of activists. Grasis was detained, Ershov managed to escape.