已知砂的筛分试验中，β--β6分别为5.4%，14%，23.4%,61.6%,82.

将用户用高级语言编写的源程序转换成目标程序是通过哪一种程序来实现的（ ）

A．编译程序

B．编辑程序

C．操作系统

D．汇编程序

It will be a while_____ the real-estate problems _____ are the root cause of the price rises are solved.

A．since, which

B．after, which

C．before, that

D．when, that

--- Would you like to go shopping with me?

--- I’d love to, ____ I can’t. I have many things to do.

A．or

B．but

C．so

D．and