1) Insert words and expressions.

Semiconductors include a great variety of (chemical compounds), (metal alloys). Minerals and crystals appear to possess some unexpected (properties). Their conductivity increases with (heating) and falls with (cooling). With the help of a ray of light directed at a semiconductor, we can effect (remote control). The semiconductor devices are applied for (automatic control) of a variety of processes, for the (transmission) of sound, (acceleration) of some chemical reactions. (Thermoelements) created in Russia convert heat directly into electricity.