he boy got his bicycle now　—Yes,the police gave

The difference in thickness and weight from the earlier version makes the iPad 2 more comfortable ____ .[ ]

You will surely realize your dream of being a scientist ______ you give it up halfway.

Why don’t we choose that road to save time?—The bridge to it _____________

Why do you look so worried — My MacBook Pro broke down and my paper _____unfinished ever since.