2. Fan Chen has developed good study purposes and habits. Fan Chen has developed good study habits.
3. The flowers on the balcony must have been watered by Grandpa. (You can only go to one without "probably" or "definitely")
4. The small football match has increased the friendship between classes. The small football match has increased the friendship between the students in each class. )
5. Although he is good at all subjects, he is never complacent. (change "so" to "but")