Correc the mistakes. ПОМОГИТЕ СРОЧНО НАДО.

Alice asks if we are ready.
They say these boxes are made of wood. (Ничего не надо менять, согласование времен еще не отменили. Просто tell здесь, как у зайца стоп-сигнал)
The boys' mother said they would buy Christmas presents the next day.
...He's been ill for three days.
...a little...
...been living here since 2002
Вообще не понял, о чем это: то ли у него есть эти маленькие монетки в коллекции (these little coins), то ли у него есть несколько монет (a few coins) в ней. В обоих случаях не вижу повода для сожаления.
The teacher wants us to write...
...made us stay

They tell that these boxes are made of wood
He has been ill for three days
...I have a few coins in my collection
the teacher wants us to write a test on monday

так. Alice asks if we are ready. His grandmother made us stay at home. С предыдущим ответом полностью соглашусь :)

Boxes were made ( в косвенной речи меняется время) , buy some jam ( jam - неисчислимое сущ).

We have lived here since 2002 а не for
Could you buy little jam, please?надо A LITTLE то же самое в 7 предложении, а лучше ANY JAM
The teacher wants us to write a test on Monday-так лучше.