Answer the questions using 's.

a) whose is that man over there? (robert- father)
b) whose is the best project (steve)
c) whose toys are these? ( the children)
d) is this your uncle? ( my cousin- friend)
e) whose dictionaries até these? (the students

A- He is Robert's father
b- Steve's project is the best
c- They are the children's toys
d- No. He is my cousin's friend
e- They are the student's dictionaries

A. Robert's father
b. Steve's
c. Children's
d. My cousin's friend
e. The student's
a. My friend's backpack
b. The boy's friend
c. Two month's holiday
d. Yesterday's newspaper
e. Paul and Tom are in the same classroom
f. Good morning, how are you?
g. Can I borrow your eraser?

Cujos(de quem) dicionários são estes? (os estudantes) 

It's Robert's father
It's Steve's
They're the children's
No,he's my cousin's friend
They're the students'

Não entendi muito bem a pergunta, porque parece que você colocou as respostas nas questões já. Mas segue aí com as traduções e também coloquei outras formas pra ficar incrementado pra dar aquela puxada de saco haha:

A) The dictionaries are theirs. Estes dicionários são deles.
B)These chairs are mine. ou ( These are MY chairs). Estas são minhas cadeiras
C) This pencil is your. ou ( This is your pencil).Esta caneta é sua.
D) This car is her. ou ( This car belongs to her). Este carro é dela. Este carro pertence a ela.
E) This briefcase is mine. ( This is MY briefcase). Esta pasta é minha. Esta é minha pasta.
F) This cat is his. ( this cat belongs to him). Este carro é dele. Este carro pertence a ele.
G) this is our bags. Esta é nossa bolsa.
H) These are their sandwiches.. Estes são os sanduíches deles.

Simples usando o 's é Estudent's

Whose are the students's dictionaries