翻译
根据下面各题的汉语意思用英语完成句子，词数不限。
至今，145个国家参加了2015意大利米兰世博会。
So far, 145 countries __________________________ the 2015 World Expo in Milan, Italy.
为了帮助中国游客养成绿色旅游的习惯，政府制定了新规则。
The government has made new rules to help Chinese tourists to ____________________ of traveling in a green way.
从五月起，北京允许盲人乘客与导盲犬一起乘坐地铁。
Starting from May, Beijing allows blind passangers ______________________ with their guide dogs.
只要你提前三个月预订，飞往悉尼的票价就会减半。
The air ticket to Sydney will be half price _______________________ it three months earlier.
多么恶劣的天气！在长江发生了严重的意外事故。
_____________________ it was! A serious accident happened on the Changjiang River.