Correction

Are these sentences correct?

1- "This article mostly aims at filling the gap in the science that how beat perception occurs in CI recipients."

2- "I became more and more interested to make a merger between music and psychology."

3- "The reason that I choose to study in a foreign country instead of my own country is first because none of the Iranian universities work in the area of music neuroscience or related fields and there is not a scientist working in this area. A few studies done in this field in my country has been carried out by some who specialize in other areas than in music neuroscience."

4- "I find it incumbent upon myself to return to my country as soon as my studies are finished to be beside her for the rest of her life. "