Please correct me. Hi. My name is Hadi. I'm trying to learn English. This is my first note. I read it in a Persian (Farsi) magazine. Please correct my entry. A strange and new method for strengthen memory! Why do you fist your hands? To show your anger? Maybe you don't believe it but based on researchers (researches of researchers) by fisting your right hand you can stable the memory of an event in your brain and help remembering it by fisting your left hand. Researchers did a study on 50 volunteers and found that persons who do this method up to 50 percent are more successful. Before researches have showed that we can prevent from Alzheimer desease by fisting hand in anger because this work stimulate that part of brain who is responsible for memory and remembering memories. Does the phrase "have showed" is correct? Thanks in advance.