Make the positive or negative past perfect The leave were yellow because it (not/Rain) all summer.

The Light went off because we (not/pay) the electricity Bill.

The students (not/prepare) for the exam, so they were in trouble.

My frinds (not/have dinner) so we went to a restaurant.

1) Victor will be free tomorrow evening
Victor was free yesterday evening
2) John will be in Africa next month
John was in Africa last year 
3) I will be very busy tomorrow 
I was very busy last week
4) She will be at the lecture at 5 o'clock
She was at the lecture on Tuesday
5) The child will be 10 yers old next month
The child was 10 years old yesterday
6) This work will be interesting
Nhis work was interesting next year
7) The expedition will be in Africa next month
The expidition was in Africa last Sunday
8) The film will be long
The film was ling
9) My mother will be at home at 10 o'clock
My mother was at home at 3 o'clock
10) The students will be in the institute on Friday
The students was in institute yesterday

Если вопрос задан к подлежащему, то вс глагол do или does не употребляется :
Who speaks English ?-Кто говорит ло английски?
Who plays the piano? - Кто играет на пианино?
В остальных случаях используется do ( we ,you, they)
They play football.
Do they play football? What do they play?
Does используется, если подлежащее стоит в 3 лице единственного числа. ( she, he, it)
н-р:
She speakS English.
Does she speak English? What language does she speak?
He playS football.
Does he play football? What does he play?
( do и does -указатели простого настоящего времени Present Simple )