解釋：
on a diet 英[?n dai?t] 美[ɑn e ?da?t]
[詞典] 節食;
[例句]Have you been on a diet? You've lost a lot of weight
妳最近在節食嗎？妳瘦了好多。
He has been on a diet for as long as any of his friends can remember
在朋友的記憶中，他壹直都在節食。
I'm forever on a diet, since I put on weight easily
我永遠都在減肥，因為我很容易長胖。
He lived on a diet of water and tinned fish
他僅靠喝水、吃魚罐頭過活。
'He'll have to go on a diet,' Ballard quipped
“他得減肥啦，”巴拉德俏皮地說。