According to the latest study，most traffic accidents     be prevented if drivers are careful enough．

---Is that Lucy’s sister, Lily?---No, it _______ be her. She has gone to English.

I don’t know what happened to my pet. It just ________ eat whatever I feed her.

---- ________ you spoil everything, Kevin?---- Please don’t get me wrong. I just want to help and I am a good man and I ….

Brain, like muscles, also needs some kind of exercise and nutrition. The more you use your brain in the right direction, the more you ________ enhance your ability.