—Have you found your lost mobile phone? —No, I haven’t. But I bought ________ yesterday. 

(2011·北京高考)The employment rate has continued to rise in big cities thanks to the efforts of the local governments to increase________.

Many people like to talk about generation gaps. I don’t think there is       in my family, though.

The cells of humans, especially _____of the brain, can live only minutes without circulating blood.

 —The phone is ringing —Who could            be? It is already midnight .