英语翻译第一句：市内电话按“0”键加电话号码,国内长途按“0”键加地区代码再加电话号码,国际长途先按“00”键加国家代码

Please press 0 button before dialing if you want to give a local call. And do likewise before dailing plus the area code if you want to make a DDD call. Please press 00 button before dailing plus the country code and the area code if you want to make an IDD call.
For your safety's sake, you'd better lock your door well. And the key should be returd to the receptionist' s desk. Please notify the assistant manager if the key is lost.