The resistance of a conductor varies （）
A. directly as its length and inversely as its cross-sectional area
B. inversely as its length and directly as its cross-sectional area
C. directly as its length and directly as its cross-sectional area
D. inversely as its length and inversely as its cross-sectional area
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Where is the most air freight shipped in the passenger aircraft?（）
A. Separately
B. In same level
C. In the lower part
D. Not mention here
电焊机在雨、雪天气室外露天作业时，应做好防护。
A. 正确
B. 错误
在神经症的脑功能失调症状中，有关精神易兴奋的叙述，正确的是（）
A. 日常生活中事无巨细均可使患者浮想联翩或回忆增多
B. 不随意注意增强，极易被周围的细微变化所吸引，以致注意很难集中
C. 患者的感受阈值降低，对内外刺激的感受性增强
D. 不同于精神运动性兴奋，常不伴有言语和动作的增多
E. 精神易兴奋常与精神易疲劳同时存在
高处作业区周围的孔洞、沟道等应设盖板、安全网或围栏并有固定其位置的措施。同时，应（），夜间还应设红灯示警。
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