----Did you look up the time of the high-speed trains to Shanghai?----Yes, the early train is __________ to leave at 5:30 a.m.

Last night, your mobile phone was always busy. I couldn’t ______ to you after several attempts. 

Information and opinion gap exercises have to have some content ______ talking about.

Obama’s success in presidential election proves that the color of one’s skin shouldn’t be a________to success.

 Every year _____ money and energy is spent on environment protection.