Thetruth  61     treesarevitaltoourlifeisnotasecret.The...

问题详情：

The truth   61      trees are vital to our life is not a secret. They provide us with food, wood and most    62      (importance), oxygen. Now there is one more thing we can add to this list—blocking out harmful bacteria from water.

The discovery    63     (make) by a team consisting of scientists from the Massachusetts Institute of Technology (MIT) and high school students who were seeking a    64     (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   65     (research), led by Professor Rohit Karnik, decided to turn to trees for help because they could allow liquid to flow through, while    66     (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.   67    their amazement, they found that it was effective in trapping all the articles.   68  (encourage), the team conducted  69     experiment, this time with water   70      contained bacteria. Sure enough, the sapwood held back 99% of the bacteria, allowing only 1% to flow through.

【回答】

 62. Importantly   made  ral  65. reserchers

66. blocking   68. Encouraged  69. another  70. thatwhich

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