每日習語：to back and fill

to back and fill
    出爾反爾/朝三暮四
    例如：You shouldn't back and fill.It's time to make your choice.
    別猶猶豫豫了。是該你作出選擇的時候了。
    Those who back and fill at the problem should be got rid of.
    那些在這個問題上出爾反爾的人應該被趕出去。