1、多选题：
According to national standard, which of the following are preferred scales?
选项：
A:5：1
B:3：1
C:4：1
D:2：1
答案: 【5：1;
2：1】

2、多选题：
Which of the following lettering heights are provided in national standards?
选项：
A:3
B:10
C:5
D:7
答案: 【10;
5;
7】

3、判断题：
The symbol "GB/T 14689-2008" denotes that the concern national standard is compulsory.
选项：
A:对
B:错
答案: 【错】

4、判断题：
When we make a drawing, a frame should be drawn inside of the outmost edges of the drawing sheet. There are two styles of drawing sheet layout: with a filling margin and without a filling margin.
选项：
A:错
B:对
答案: 【对】

5、单选题：
Which of the following lines are used as dimension lines, extension lines, leader lines, construction lines, section lines and projection lines?
选项：
A:Thin phantom lines
B:Wavy lines
C:Thin center lines
D:Thin solid lines
答案: 【Thin solid lines】