Tornadoes (Simple present and present progressive)

Tornadoes ​ (a)   in most areas of the world.

• occur
• are ocurring

However, the plains of the United States ​ (a)   the most. (Plains are large areas of flat land with few trees.)

• have
• are having

Tornado Alley, a frequent area for tornadoes, ​ (a)   from Texas to North Dakota.

• stretches
• is stretching

Because tornadoes ​ (a)   over flat areas of land, they ​ (b)   so common in the mountains.

• form
• are forming
• are not
• do not

Cold air ​ (a)   warm air, usually in a thunderstorm.

• meets
• is meeting

The winds ​ (a)   a spiral or funnel cloud that sometimes reaches 320 miles per hour.

• make
• are making

They ​ (a)   cars, trees, and houses.

• pick up
• are picking up

Sometimes this debris ​ (a)   for miles.

• flies
• is flying

Strong tornadoes ​ (a)   a lot of damage.

• cause
• are causing

Surprisingly, the funnel cloud ​ (a)   long, usually less than ten minutes.

• doesn't last
• isn't lasting