A national political struggle is continuing over the issue of protection for the remnants (剩余,残余)of vast ancient forests that were once covered 【M1】 ______ the northwestern areas of the United States. These old forests, calling' old 【M2】 ______ growth', contain trees form. 200 to 1, 200 years old. There are now about 6 million acres of virgin forest in Washington and Oregon, only about one- tenth of what existed before the 1800s. This old-growth area contain some 【M3】 ______ of the most valuable timber in the nation, but its economical worth is also 【M4】 ______ contained in its water, wildlife, scenery, and recreational facilities. Conservationists want the majority of existing old growth protected from harvesting. They emphasize on the vital relationship between old growth 【M5】 ______ and the health of the forest's ecosystem. They cite studies that show that both downed and stood old trees store and release nutrients necessary to younger 【M6】 ______ trees. On the other hand, many of the Northwest's economy is developed 【M7】 ______ around the logging industry. Trees are cut down to make wood products, and many mills are geared for old-growth industry. In recently years, 500 acres 【M8】 ______ of old growth have been logged, excluding trees up to 500 years old and eight 【M9】 ______ feet in diameter. As the U.S. Forest System wrestles(全力对付)with the problem of how much of the forest to save, the harvesting of timber continues. The district office refuse to remove any of the old growth from timber production. The struggle is continuing at the national level, with strong proponents on all sides. 【M10】 ______ 【M1】
A. B. C.S.
【参考答案】
were once covered改成once covered were once covered改成once ......