There is an interesting and useful resource where you can practice your writing test and Cambridge will write you back with their corrections of your writing task.
What to do? How to work with it?
First, click on this link WRITE AND IMPROVE
Then, create a profile with your email, sign in with the password and look at in your level list.
There you will find similar tasks to what they are going to ask us in the Cambridge test on the 23rd of May, such AN EMAIL, AN INVITATION, A NOTE, A LETTER, A STORY, etc.
I hope it will help you (FUTURE PREDICTION)
Good Luck!!
