Lesson 4 | The Cenozoic Era

sentence can be clues to use the simple past tense. Hundreds of millions of years ago, the North American continent straddled the equator. In the Late Paleozoic period, Earth’s landmasses combined into the supercontinent Pangaea. For regular verbs, the past tense is formed by adding –ed to the base verb (verb + –ed; for example: expanded). ................
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