试述聚乙烯的优点？
参考答案：
质地柔软，不易老化；耐低温，抗冻性好；密度小，材料用量省；抵抗芦苇、杂草的穿透能力比聚氯乙烯小。
an English party in our school this evening.[ ]
A. There will be
B. There is going; to have
C. There will have
D. There is going have
菜单命令中有“…”标记表示该命令是______的命令。
