A tsunami is (1)______ very large ocean wave, which is caused by an underground earthquake. It is caused by the force of the moon, sun, or planets or by the wind along with it. The water flows straight during a tsunami. This is different (2)______ the way ordinary waves flow. They flow in a circular pattern. This straight movement of the tsunami (3)______ a great deal of damage to the land. Tsunamis begin due to a movement of the seafloor. They can be caused by an earthquake, a volcano or a big landslide into the ocean or under it. Usually, two tsunamis a year occur around the world near the source of the earthquake or another movement. About every fifteen years, a huge tsunami happens (4)______ can affect the waters worldwide. 1. A. the B. a C. an D. x 2. A. from B. with C. in D. on 3. A. makes B. results C. causes D. leads 4. A. who B. why C. what D. which