系统允许为下列哪个选项添加自定义？（）
A.图纸集和图纸
B.图纸集和子集
C.子集和类别
D.子集和图纸
参考答案：A
Look and match．（看图片，将内容一致的图片的标号填在句子前面的括号里。）
( )1. Jane is playing football.
( )2. He took a lot of photos in London.
( )3. I bought some fruit last Saturday.
( )4. He sang songs for us yesterday.
发现室外着火，门已发烫时，是否应迅速开门逃生？为什么？
