How does waves occur and can somebody explain to me about simple past tense?

Well to understand waves, you need to first understand how wind works. The wind is cause by solar heating, when the sun shines down on the planet, not all places heat the same, due to environment, clouds, etc., during the heat process, the sun warms up the air, which causes the air to become less dense and rise, cold air, then swoops in underneath, thus creating wind. The wind is what creates the waves because its an outside force pushing upon the waters surface, over a vast distance and a strong enough wind we can get pretty big waves. A little experiment you can do is taking a bowl of water and try out blowing on the surface to create waves, give more power to your breath to see a bigger effect.

Simple Past tense is explaining to somebody or something what you have done in the past. Example: Present tense: I am travelling in my car. Future tense: I will travel in my car. Past Tense: Yesterday I was travelling in my car. The key word is the use of your action word (Pr.T: I am, F.T: I will, Pa.T: I was)

Let me know if you need some more help, or more examples :D

http://www.englishpage.com/verbpage/simplepast.htm...

http://www.perfect-english-grammar.com/past-simple...

Hope it helps.