1. Rain is a source of precipitation which (form) when separate drops of water (fall) to the Earth’s surface from clouds. Not all rain (reach) the surface; some of it (evaporate) while falling through dry air. When none of it (fall) to the ground, it is called Virga, a phenomenon often seen in hot, dry desert regions. The scientific explanation of how rain forms and falls (be) called the Bergeron process.

Source: “Cloud” Retrieved from en.wikipedia.org/wiki/Cloud on August 15, 2010

2. iPod Classic models (store) media on an internal hard drive, while all other models (use) flash memory to enable their smaller size. As with many other digital music players, iPods also (serve) as external data storage devices. Storage capacity (vary) by model, ranging from 2 GB for the iPod Shuffle to 160 GB for the iPod Classic. All of the models (have) been redesigned multiple times since their introduction.

Source: “Ipod” Retrieved from en.wikipedia.org/wiki/IPod on July 9, 2010