Rewrite the fllowing sentences

I do not have a sister.
I wish I had a sister.
In the 18th century, jean cloth was made completely from cotton.
Jean cloth used to be made entirely from cotton in the 18th century.
Rice is grown in tropical countries.
Rice is cultivated in tropical countries.
A new style of jeans has just been introduced in the USA.
A new style of jeans has recently been introduced in the USA.