Maple trees are thought to be fall color trees or foliage trees.

5. What is the passage mainly concerned with? ______ A. The benefits of trees. B. Trees and soil protection C. The various uses of trees. D. Different attitudes toward trees. A: The benefits of trees. Trees and soil protection C. The various uses of trees. D. Different attitudes toward trees. B: Trees and soil protection The various uses of trees. D. Different attitudes toward trees. C: The various uses of trees. Different attitudes toward trees. D: Different attitudes toward trees.

The mountains were covered with trees. The trees were many different varieties.

5. What is the passage mainly concerned with? _____ A: The advantages of trees. B: Trees and soil protection that can help people live longer. C: The various uses of trees and soils. D: Different attitudes toward trees.

One-third of the area _____ covered with green trees. About seventy percent of the trees _____ been planted.

262.30 % of the young trees, attacked by diseases, ________pine trees. A: is B: are C: was D: has been

中国大学MOOC: The shape and form of the bark differ not only in the variety of trees but also in age. In other words, the bark on young trees may appear distinctively from that on more __________ trees.

The apple trees have lots of big apples ________ them. And some birds are singing ________ the trees. A: in; on B: at; in C: on; in D: with; through

_____ of the trees in the garden are apple trees. A: Two third B: Two thirds C: Second third D: Second thirds

One-third of the area _____ covered with green trees. About seventy percent of the trees ____ been planted. A: are; have B: is; has C: is; have D: are; has