The text below is for the following question.

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Do not waste your old things. Recycle them into something new. If you have a plastic bottle and zip, you can turn them to be a pencil case. Get cutter/scissor and glue to help you.

First of all, cut the plastic bottle into two pieces. Don't worry about the length of the two pieces. Second, take the zip. Use glue to stick the zip around the cut side of the plastic bottle. Take another piece of the plastic bottle and stick it to another side of the zip. Wait until the glue is dry. Third, try to open and close the zip. If you want, you can add some glitter to make it cuter. Now your new pencil case is ready.

'... you can turn them to be a pencil case.' (line 2).

The word them in the sentence above refers to ....