8. Electronic dictionaries are now common in English classes. They can be very easily downloaded into your personal electronic device. (Relative clause)
Electronic dictionaries, which can be very easily downloaded into your personal electronic device, are now common in English classes.
9. Some students prefer a strict teacher. This teacher tells them exactly what to do. (Relative clause)
Some students prefer a strict teacher who tells them exactly what to do.

1. Electronic dictionaries, which can be very easily downloaded into your personal electronic device, are now common in English classes.

2. Some students prefer a strict teacher who tells them exactly what to do.