The volunteers a lot of help to the community for nearly ten years.

This is 3-D printer. And this is an artificial (人工的) ear. Can you believe that scientists printed this artificial ear by this 3-D printer?

Mom, where’s my backpack?－You shouldn’t put your things casually, you should take good care of _____ own things.

____ you are, _____ mistakes you’ll make.

You can _____ this T- shirt in the fitting room over there.