Read the following passage and choose the best answer (A, B, C, or D) to complete the passage.

Câu hỏi :

Read the following passage and choose the best answer (A, B, C, or D) to complete the passage.

TREES FOR LIFE

Trees are amongst the biggest and longest-living things on Earth, some dating back longer than the oldest buildings. But as well as being nice to look at, trees also (21) ___________ an important role in improving the quality of our lives.

On a world-wide scale, forests help to slow down the effects of global warming by using up the gas known as carbon dioxide and giving (22) ___________ the oxygen we need to breathe. At local neighborhood level, trees also brings important environmental benefits. The offer shade and shelter, which in (23) ___________ reduces the amount of energy needed to heat and cool nearby buildings; at the same time, they also remove other impurities from the air we breathe.

Urban trees are especially important because for many people they provide the only daily (24) ___________ with the natural world. What’s more, urban trees also provide a home for birds and small animals. Without the trees we would lose the pleasure of seeing these creatures in our cities. Regrettably, (25) ___________ trees in cities are now coming under threat. There is a limit to the level of pollution they can (26) ___________ and down at street level, their roots are being seriously disturbed by the digging needed to make way for telephone, television and other cables.