【单选题】The author says that in some hot and dry areas it is advisable to ______.
A.
build big lakes to store water
B.
construct big pumping stations
C.
build small and cheap irrigation systems
D.
channel water from nearby rivers to cropland
【单选题】The author says that in some hot and dry areas it is advisable to ______.
A.
build big lakes to store water
B.
construct big pumping stations
C.
channel water from nearby rivers to cropland
D.
build small and cheap irrigation systems
【单选题】液态制冷剂在蒸发器中下吸收被冷却对象的热量而()
【判断题】非必需营养素是指人体不一定要补充、吸收的营养素。()
【单选题】The author says that in some hot and dry areas it is advisable to ______.
A.
build big lakes to store water
B.
construct big pumping stations
C.
channel water from nearby rivers to cropland
D.
build small and cheap irrigation systems
【简答题】产能营养素一般是指______、______、______。