Ответ:

1)I saw her when she was playing tennis

he found us when we were climbing a tree.

she noticed the boys who swimming across the river.

2)I was heard girl who was crying

she was observed playing the violion.

you were noticed a girl running away.

3)вот эт я непоняла

4)the weather being very cold,she had to stay at home

her daughter having fallen ill,she sent for the doctor.