21. The computers that we use at the moment are old and slow, and they often ________ and are not connected to the Internet.
A. break B. crash C. contract D. react
22. This button is designed to give the users easy and quick _______ to Facebook, no matter what they happen to be doing on the phone.
A. access B. passage C. way D. approach
23. Many people have come to realize that they should go on ________ balanced diet and make room in their day for _______ exercise.
A. /; an B. the; an C. the; the D. a; /