一个数的2.5倍加上0.75等于7，求这个数．
（7-0.75）÷2.5，
=6.25÷2.5，
=2.5；
答：这个数是2.5．
_______ the one-child policy, our country has controlled the population successfully.
A. Thanks to B. Thanks for C. As for
会员单位应逐步建立科学、规范的（）机制。
A、理念
B、服务
C、会员
