Overview

First of all, here is a very nice overview of all tenses of the English language (pdf).

If you are not sure when to use which tense, this graphic comparison might be of some help. (Yes, there is also a German version, but you have to find it on your own.)


Exercises

The following websites provide numerous grammar exercises:

Of course, knowing the tenses and being able to fill in gaps is not enough. You will also have to write sentences or even texts, stories, diary entries, letters, etc. (see the "writing" page for more details) on your own. That's why you need to know the word order of English sentences.

When you have worked yourself successfully through all these exercises, you will definitely not end up like Ralph Wiggum of the US TV show "The Simpsons", who once said: "Me fail English? That’s unpossible!"