- come into force; start to apply
- become operative; start to apply
Oxford American Dictionary
B is grammatically incorrect. In order for B to be correct, B will have to state "On July 17th."
...new rule (新規定) 而不是 news rule (新聞規則?)吧!1. The new(s) rule, which takes effect Tuesday (此形容詞子句為非限定用法,所修飾的先行詞為唯一的事物), may...
This contract will take effect immediately. Each party will keep one of the two original copies. 2007-07...