Reading & Writing: Fill in the Blanks — practice #rwfib-008

Renewable energy sources such as wind and solar power are becoming an increasingly — choose —importantdoubtfuldistantsecret part of the electricity supply. Because their output — choose —repeatsvanishesvariesfreezes with the weather, engineers must find ways to store surplus energy for later use. Large batteries and pumped-water systems can — choose —destroyreleasewastehide this stored power during periods of high demand. Many governments now offer financial — choose —delaysincentiveswarningspenalties to encourage households to adopt cleaner technologies.