Nucleus consist of neutrons and charges.
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Insulators allow free electrons to move freely thoughout the solid.
A. 对
B. 错
If the atom loses electrons, it becomes positively charged.
A. 对
B. 错
硝酸甘油用于防治心绞痛时，效果最好的给药途径是
A. 口服
B. 舌下含化
C. 雾化吸入
D. 软膏涂于前臂、胸及背部皮肤
E. 直肠给药
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