Слайд 2
There is a speed in studying language which a group moves with. If
one of the group misses a class, then at the next lesson he may not get something that was learnt by the others. So in many language schools and centers the money for missed classes are not returned and classes may be not worked out.
Слайд 3
If a group is gathered not so illiterately and the levels of students
differ, someone may feel boring and another can have big difficulties.
Слайд 4
For shy pupils and those who like working individually it most likely may
be uncomfortable to participate in group work and cause a comparing to anothers (from that may appear negative thoughts and opinion about self).