Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 46 to 50
In many cities worldwide, urban development is having a direct impact on the weather. It has been noticed that the difference in temperature is usually greater at night and the phenomenon occurs in both winter____46____summer. Experts agree that this is due to urban development, when open green spaces are replaced with asphalt roads and tall brick or concrete buildings. These materials retain heat ____47 by the Sun and release it through the night. In Atlanta, in the US, this has even led to thunderstorms which occur in the morning rather than, as is more common, in the afternoon. Large cities around the world are adopting strategies to ___48___ this issue and it is not uncommon to find plants growing on top of roofs or down the walls of large buildings. In Singapore, the government has pledged to transform it____49____a "city within a garden" and, in 2006, they held an international competition calling for entries to develop a master plan to help bring this about. One outcome was the creation of 18 "Supertrees" – metal constructions___50__ resemble very tall trees. Each one is a vertical freestanding garden and is home to exotic plants and ferns. They also contain solar panels used to light the trees at night and also containers to collect rainwater, making them truly self-sufficient.
(Adapted from "The Official Cambridge Guide to IELTS" by Pauline Cullen, Amanda French and Vanessa Jakeman)