This a pen___________ I lost.
This is a pen which I lost.
or
This is a pen that I lost.
This is a phone who I lost.
This is a phone which I lost.
or
This is a phone that I lost.
pen + I used today
This is a pen that I used today.
or
This is a pen which I used today.
This is a food that we eat on birthdays.
Cakes
my mom / which / These / the cookies / are / baked.
These are the cookies which my mom baked.
It is a cake _______ she baked last night .
It is a cake that she baked last night.
or
It is a cake which she baked last night.
This is a car who I bought last year.
This is a car which I bought last year.
or
This is a car that I bought last year.
bag + my friend gave me.
This is a bag that my friend gave me.
or
This is a bag which my friend gave me.
This is a thing which we use to open a lock.
A key
a game / yesterday / It / is / that / the boys / played.
It is a game that the boys played yesterday.
This is a book _______ he ___________ yesterday.
This is a book that he (verb) yesterday.
or
This is a book which he (verb) yesterday.
Look at the picture what my friend painted.
Look at the picture which my friend painted.
or
Look at the picture that my friend painted.
picture + I drew yesterday.
This is a picture that I drew yesterday.
or
This is a picture which I drew yesterday.
It is a device that we use to take pictures.
Camera or Smartphone
It / that / broke / last week / is / a chair / he
It is a chair that he broke last week.
It is a cat _________________________________.
It is a cat that (subject) (Complement)
or
It is a cat which (subject) (Complement)
Here is the book who you gave to your friend.
Here is the book which you gave to your friend.
or
Here is the book that you gave to your friend.
bicycle + his father bought for him
This is a bicycle which his father bought for him.
or
This is a bicycle that his father bought for him.
This is a thing that we use to enter the airport.
Passport
a house / This / bought / last year / is / that / they
This is a house that they bought last year.
This is a _________________________________________.
This is (Noun) which (subject)(Complement).
or
This is (Noun) which (subject)(Complement).
These are the glasses what you break yesterday.
These are the glasses that you broke yesterday.
or
These are the glasses which you broke yesterday.
movie + he watched ________.
It is a movie that he watched (Complement).
or
It is a movie which he watched (Complement).
It is a thing which we use to listen to the music quietly.
Headphones or Airpods.
my teacher / gave / Here / a book / is / which / me.
Here is a book which my teacher gave me.