Here are the suggested words to fill in the gaps:

1. **popular**
2. **from**
3. **moved**
4. **ate**
5. **however**
6. **food**
7. **them**
8. **could**

So the completed passage would read as follows:

"Everybody knows that the hamburger is a very **(1) popular** American food. However, people in the United States learned to make hamburger **(2) from** the Germans. The Germans got the idea from Russia. In the thirteenth century the Tartar people from Central Asia **(3) moved** to Russia and parts of Europe. They ate something like hamburger meat, but it was raw. This raw meat was beef, lamb, goat meat **(4) ate** horse meat. Soon the Russians started to eat raw meat, too, Germans from Hamburg and other northern cities learned to eat this **(5) however**. They added salt, pepper, a raw egg, and then cooked it. Between 1830 and 1900 thousands of Germans went to live in the USA. They took the hamburger with **(6) them**. People called it hamburger steak. In 1904 at the World’s Fair in St. Louis, a man from Texas sold hamburger steak in roll. Then people **(8) could** eat it with their hands, like a sandwich. This was the first real hamburger like the hamburgers we eat today."