• 2022-06-01
    Selective cutting
    A: encourages crowding of trees.
    B: encourages growth of more mature trees.
    C: maintains an uneven-aged stand of trees of different species, ages and sizes.
    D: requires a special seed distribution plan.
    E: requires crop rotation.
  • C

    内容

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

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

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      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

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

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      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