1.

One of the most rewarding aspects of  is seeing them develop so quickly.

2.

The most challenging thing about  is finding the time.

3.

One of the rewards of  is having a lot of time for yourself.

4.

One of the most difficult things about  is having to get grades.

5.

The most interesting aspect of   is the flexible schedule you can keep on every English course.

6.

One of the least interesting aspects of is waiting around a lot.