Novice teacher
One-to-one TOEFL courses are mostly taught by novice teachers, and good teachers teach in large classes. Therefore, if you want to sign up for one-on-one courses, you need to consider the level of teachers.
More cost-effective
In contrast, large classes are more cost-effective. Because large classes can gather more students, the tuition fees are relatively low and the teachers' level is high.
Poor foundation or tight time?
If your TOEFL foundation is poor, or your time is particularly tight and your self-control is not good, then you can consider one-on-one counseling. Because it can concentrate more on study and improve efficiency.
Wise choice
Generally speaking, one-on-one TOEFL course is not suitable for everyone. If you want to sign up for one-on-one courses, you need to consider your own actual situation. Large classes are a common choice, because they are more cost-effective and have higher teachers' level, which is suitable for most students.