For such an important part, you want to be sure they're working properly.

But he could not seem to make his arms work properly.

The system of security we have now is not working properly.

About the fact that part of my mind just didn't seem to work properly.

Use them to make sure that they are working properly.

I tried to return it, but my face was not working properly.

Even when 3-D is working properly, it takes some getting used to.

First, I want to be sure that the control board is working properly.

You may make a good deal of that little fact if properly worked.

Tom wanted to see if his camera was working properly.