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how do you learn tense in english easily?

Try learning all the different tenses together. For example, study the Past Simple Tense, then the Present Simple Tense, then the Future Simple Tense. Look for examples where you can use these tenses in everyday discussion. There are many TEFL Grammar books on the market that have a clear and simple explanation of grammar. It is important that you learn when to use each tense and how. Take it one at a time, until you can use them confidently. As Leigh Mumford said, practice!

The simple tenses are a good start for an absolute beginner. Then, add the continuous tenses and learn the differences between them (eg. the difference between "I walk" and "I'm walking"). Build from there.

You'll find that the tense you need depends on the context.

apply the tenses in your real life, for example by writing a note book or message to your friend