resposta:

1)

a) He was a student

b) It was white

c) He was my friend

d) She was a teacher

e)They were married

f) She was alone

g) We were going to sleep

h) We were playing

i) They were studying together

j) It was yellow

2)

a) Was he a student? / He wasn't a student

b) Was It white ? / It wasn't white

c) Was he my friend? / he wasn't my friend

d)  Was she a teacher? /She wasn't a teacher

e) Were they married? / They weren't married

f) Was she alone? / She wasn't alone

g) Were we going to sleep? / We weren't goingo to sleep.

h) Were we playing? / we weren't playing

i) Were they studying together? / they weren't studying  together

j) Was it yellow? / It wasn't yellow

Explicação:

Bom primeiro para passar no passado você irá sustituir os sujeitos pelos pronomes, por exemplo: Allan está na terceira pessoa ou seja: He (He é o pronome da terceira pessoa do singular usado no masculino), The dog = It ( It é usado também na terceira pessoa, porém ele só será usado para coisas, objetos que não sejam pessoas), Polly = She (She é o pronome da terceira pessoa do singular usado no feminino), Me and my mother = We (Será usado we porque somos eu e minha mãe sendo assim nós) Isa and Jhon = they (será usado they porque são eles).

No exercício 2 para passar para interrogativa  flexão verbal was/were deve ser posicionada antes do sujeito e para passar para a forma negativa basta acrescentarmos not após o verbo (lembrando que ali está na forma contrariada: was + not = wasn't e were + not = weren't)

Espero ter ajudado, ficou grande pois tentei explicar direitinho e espero que você tenha conseguido entender. Bons estudos e boa sorte <33