May I ______ whole-heartedly into the fight

__________ to smart phones just before bed, as a research says recently, can lead to poor night’s sleep.

I thought you ____ like something to read , so I have brought you some books .

In many countries more and more forests and even agricultural land are being lost to development, _______ much of the land to become desert.

Even students of average intelligence ________ become top students by improving their study habits.