9時から8時半に出社時刻が早まりました。”We’ve been (supposed/ have) to start working 30 minutes earlier than before since the day one in April.” と考えましたが自然な表現ですか？ネイティブが使う自然な表現を教えてください。
Since April, the beginning of the work day has been moved up by 30 minutes.
The start time was moved up from 9 to 8:30.
We've been starting work 30 minutes early since the beginning of April.
「4月から始業時間が30分早まった」は英語で「Since April, the beginning of the work day has been moved up by 30 minutes.」という表現が良いと思います。「We've been starting work 30 minutes early since the beginning of April.」も良いと思います。「9時から8時半に出社時刻が早まりました。」には「The start time was moved up from 9 to 8:30.」という表現も自然だと思います。
アメリカ合衆国 
