X光管保持高真空度的原因是（），并保持灯丝不氧化。
参考答案：可不受气体分子阻挡而消耗能量
巴豆的功效是
A．泻水逐饮，消肿散结
B．泻下，逐水，去积，杀虫
C．泻水逐饮，祛痰止咳
D．泻下，软坚，清热，回乳
E．泻下冷积，逐水退肿，祛痰利咽，蚀疮去腐
You want to invite Susan to a party. Write an invitation letter to her, elaborating on the reason why such a party should be held and what activities will be arranged for them.
Do not sign your own name at the end of the letter. Use "Li Ming" instead.
Do not write the address.
