The skin, an ____ part of your body and its largest organ, ____ as a barrier against diseases.[ ]

The politician has been warned that he would be getting into great trouble_____stick to his standpoint.

As we all know, one unfortunate outcome of Internet use is that it damages people’s ability _______ normal lives.

When you go outing with your sisters, you must see to_____ that they are safe. 　　[ ]

Wouldyou please ______ the paper for me and see if there are any obvious mistakes