In 1620,about half the USA__forest.In 1620,about half the USA__forest.A.was covered B.was covered by C.were filled with D.covered with如果D选项是be covered with呢
问题描述：
In 1620,about half the USA__forest.
In 1620,about half the USA__forest.
A.was covered B.was covered by
C.were filled with D.covered with
如果D选项是be covered with呢
答
B 被森林覆盖（全是森林）
答
B. 被...覆盖
译为:在1620年,差不多半个美国被森林所覆盖.
如果D选项是was covered with,那么就选D.但be covered with可不行.
答
B
A 加个with
C 表示空间不表示平面
D 缺少谓语
答
选b