用 there is there are there was there were 分别造三个句子

There is a cat on my desk.
There is a flower in front of my computer.
There is 50 dollars in my pocket.
There are some boys palying ong the groud.
There are 5 books under the chair.
There are a lot of people buying roses on Valentine's day
There was a car there last night.
There was nobody in my home last Thirsday.
There was a pen in my book the day before I went home.
There were aroud 20 people in my home last Satarday night.
There were several hundreds athletes taking part in the sports meeting.
There were more than one hundred people taking part in my wedding.