I strongly disagree with the statement saying that "At school, students should only study what they enjoy".

strongly 是形容词 strong（强烈的）加上后缀 -ly 构成的副词形式，表示"强烈地、坚决地"。 disagree 由前缀 dis-（表示否定）和动词 agree（同意）组成，意思是"不同意、反对"。