1与decision搭配的动词 应该用make ,agreement 才用reach
2 前半句有些累赘
3 must 改为have to 感觉更好
A decision has been made but has not yet been announced.We have to wait until 4 o’clock,that is when it will be announced.
这是我的修改意见
过去完成时要以过去时的出现为前提 此处并没有用到过去时 所以不宜用 不过可以把开头改为A decision was made...其余不变