1) We wouldn't help you if we(not want) to.
2) I(buy) you a resent if you are good.
3) If I were you, I(buy) a more reliable car.
4) I(not complain) if I had their lifestyle!
5) If they(not pass) their exams, they'll be so disappointed.
6) He(not do) such a dangerous job unless he enjoyed it.
7) If you(not ask) for a pay rise, you won't get one.
8) His teacher won't be angry if he(tell) her the truth.
9) If I(have) better qualifications, I could be a teacher.​

Surveillance is a really important innovation in our times as it helps to closely observe a suspected spy or a criminal. Public cameras ensure public safety, Through surveillance cameras, the police can both prevent crimes from happening and can quickly solve criminal cases with material evidence. In addition, surveillance cameras protect against property theft, and vandalism. Well, surveillance also has it's disadvantages. It can cost a lot and cause problems with an individual's privacy. In addition, they can help and watch the crime or help police to arrive earlier, but they do not prevent it.

The Past Simple Tense:

yesterday - вчера

ночью (вчера вечером)

a year ago - год назад

then - тогда, затем, потом

last year - в году

when - когда

in 1980 - в 1980

last month - в месяце

a minute ago - минуту назад

The Present Perfect Tense:

already - уже

just - только что

never - никогда

ever - когда-нибудь

yet - ещё, пока

since - с, с тех пор (как)

how long - как долго

* always - всегда (обычно используется в Present Simple Tense, но из предложенных выше времён я бы отнесла его в Past Simple)

*never - никогда (иногда тоже можно употреблять в Past Simple,но реже, чем в Present Perfect)