题目内容
阅读下面材料,在空白处填入适当的内容(1个单词)或括号内单词的正确形式。
The truth 1. trees are vital to our life is not a secret. They provide us with food, wood and most 2. (importance), oxygen. Now there is one more thing we can add to this list—blocking out harmful bacteria from water.
The discovery 3. (make) by a team consisting of scientists from the Massachusetts Institute of Technology (MIT) and high school students who were seeking a 4. (nature) water filter(过滤器)—one that would help communities in developing countries that do not have access to modern water filter systems.
The 5. (research), led by Professor Rohit Karnik, decided to turn to trees for help because they could allow liquid to flow through, while 6. (block) out air bubbles.
They began by cutting 1.5-inch-wide sections of tree bark from the branches of a white pine tree. The people related then tested the wood’s filtering ability by pouring water containing red dye particles of different sizes through. 7. their amazement, they found that it was effective in trapping all the articles. 8. (encourage), the team conducted 9.________experiment, this time with water 10. contained bacteria. Sure enough, the sapwood held back 99% of the bacteria, allowing only 1% to flow through.