Read the paragraph and complete the gaps.follow friendship.emotions.When people meet for the first time they​

The white tiger is an individual of the Bengal tiger with a congenital mutation (not considered a separate subspecies). The mutation leads to a completely white coloration - a tiger with black-brown stripes on white fur and blue eyes. This color is very rare among wild animals. The frequency of appearance of white tigers is 1 individual per 10 000 with normal color. Reports of the white tiger for many decades came from Assam, Bengal, Bihar and especially from the territory of the former indigenous principality of Reva. The first discovery of the white tiger in nature, however, is attributed to 1951, when one of the hunters took a white male tiger from the lair that he had found and then unsuccessfully tried to obtain from him the same progeny from the female with normal color, but then after all succeeded in creating a second generation of white tigers. Over time, the population has significantly expanded: all white tigers, which are now contained in captivity, are descendants of the same found individual and have a relationship with each other. Now in captivity contains about 130 white tigers, about 100 of them - in India. The last known white tiger in nature was shot in 1958. The view that white tigers are albinos is wrong - in fact, this coloration is caused by the presence of recessive genes (a real albino tiger would not have black bands). If both parents are heterozygous, that is, orange, but are carriers of genes, then the chance to get their offspring in the form of a white tiger is 25%. Parents, one of whom is a white tiger, and the other an orange heterozygote, has a similar chance to increase up to 50%. If one of the parents is white and the other is orange, but homozygous, the whole offspring will be orange, but the carriers of the gene. White tigers are usually smaller (from childhood) than ordinary Bengal tigers, and often, due to closely related crossings, [1] have various genetic defects, including strabismus, poor vision, clubfoot, curved spine and neck, problems with kidneys. Nevertheless, the claim that infant mortality among white tigers is extremely high does not really correspond to reality. White tigers are popular not only in zoos, where they are often attracted to everyone's attention and are therefore considered a valuable specimen, but also in popular culture: in particular, some musical groups dedicated songs to them. I want this breed of tigers to be protected and not killed! Thank you for attention

The door is closed. Дверь закрыта.
• The song was sung. Песня была спета.  

2. Неизвестно, кто

Субъект, совершивший действие, неизвестен.

• The crime was committed. Было совершено преступление.
• It was stolen. Это было украдено. 

3. Неинтересно, кто

Субъект, совершивший действие, неинтересен - речь совсем не о нём.

• The house will be painted blue. Дом будет покрашен в голубой цвет.

4. Вежливый отказ

• Your request was rejected. Ваша была отклонена.
  Вместо: я отклонил вашу

Как всё-таки упомянуть того,  кто совершил действие? Взять этого субъекта и поставить его в конец предложения, на место дополнения:
• The patient was seen by a doctor. Пациент был осмотрен доктором.
• The order was finally made by ​​them. Заказ был, наконец, выполнен ими.

by выражает творительный падеж
кем? - мной, им: by me, by him

Правила разобраны. Примеры приведены. Знай - выбирай, в активе выразиться или в пассиве.

 актив 
  He
 
  loves
 
  her
    Он  любит  её   подлежащее  сказуемое    дополнение   или пассив 
  She
 
  is loved
 
  by him
    Она   любима  им   подлежащее    сказуемое  дополнение

Если выбран пассив, значит, пригодится третья форма неправильных глаголов.

• Everything will be done. Всё будет сделано.
• The job is done. Работа сделана. 

do - did - done.  делать

• The house will be built next year. Дом будет построен в следующем году.

build - built -built.  строить

С правильными проще: invite - invited.

• I was invited. Я был приглашён.

как то так