3.What is the average depth of the
lake?
a) 500 metres
b) 400 metres
c) 300 metres​

average depth 0.8-1 m, maximum - 2.5 m.

+                                           ?                                         -

i was                                 was i?                               i was not(wasn’t)

he/she/it was                   was he/she/it?                     he/she/it was not (wasn't)

we were                             were we?                         we were not (weren’t)

you were                           were you?                         you were not(weren’t)

they were                           were they?                         they were not (weren’t)

будь так добр, волошин, поставь мне "лучшее решение"!

.1.-open the window.

-but i have opened the window.

2.i have seen the film.

3.he has opened the door.

4.they have cleaned the room.