Question

Когда надо писать was или were ?

Answer 1

Was, когда единственное число. Were, когда множественное число. 

Answer 2

Was - he she it прошедшее время
Were - we you they тоже прошедшее

Answer 3

"Was" and "were" are both forms of the past tense verb "to be." "Was" is used with singular subjects, such as "he," "she," "it," or singular nouns (e.g. "The car was blue"). "Were" is used with plural subjects, such as "we," "you," "they," or with the pronouns "I" and "she" (e.g. "We were at the park"). It's important to match the subject of the sentence with the correct form of "to be" in the past tense.