小麦播种时，土壤耕层水分应保持在田间持水量的30－40%。

小麦播种时，土壤耕层水分应保持在田间持水量的（）。

根据根据茶园土壤特性选择肥料

砂土的容重（）于粘土的容重，总孔度（）于粘土，密度（）于粘土。

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

论述土壤在农业生产和自然环境中的作用。

下列哪种肥料元素在土壤中移动性强。（）

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

花卉生长需要的水分主要依靠（）从土壤中吸收。