A strange smile

Mr.alex was a teacher in D.A.V Public school . He was a slave of his thoughts . One day, during his class ,one of his student was continuously starring at him , without blinking her eyes .Her expressions was very strange with a strange smile on her face . Alex fell awkward but can't tell her to stop . But he tried to ignore her every time . But the next day , the same girl during the leisure period went to the staff room , and opened Mr. Alex's bag and with a strange smile she put something in his bag(secretly). can you answer me why that girl was showing her strange behaviour towards Mr.Alex ?🤔in comment box.