Today is Saturday. The weather is warm and sunny. Bob and Jack go to the park. There are many people there. The girl under a big tree is reading a book. Two boys are playing football on the grass. The girl in a red dress is riding a bike. Two women are talking. The man beside these women is playing with a baby. Bob and Jack are beside the river. They are sitting on the chair and drawing pictures.

A $\underset{①}{\overset{C{l}_2,光照}{\to }}$   （一氯环己烷） $\stackrel{②}{\to }$   $\underset{③}{\overset{B{r}_2的CC{l}_4溶液}{\to }}$  B $\stackrel{④}{\to }$  

近年来，中央加大简政放权力度，着力“把错装在政府身上的手换成市场的手”。政府取消下放行政审批项目是做减法，但其最终目的是要做加法。下列对所说的“加法”理解正确的是（    ）

①增设相应机构，更好地履行基本职能        ②扩大政务公开，拓宽民主监督的渠道

③健全相关制度，加强对市场主体监管        ④强化效能建设，提升服务和管理质量