A.Vitamin A deficiency results in night blindness, which is also known as nyctalopia in medical terms.
B.The earliest sign of vitamin A deficiency is night blindness.
C.Among many disorders caused by lack of vitamin A, night blindness is the most common.
D.Vitamin A deficiency may cause many different types of ailments especially involving the eyes, including nyctalopia.
第1题
质量流量计的主要特点之一是可直接测量(),与被测介质的温度、压力、粘度、密度变化无关。
A.体积流量
B.质量流量
C.批量流量
D.累积流量
第6题
A.差压式质量流量计
B.刮板流量计
C.科氏力质量流量计
D.叶轮式质量流量计
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