vicious circle

1. N-COUNT A vicious circle is a problem or difficult situation that has the effect of creating new problems that then cause the original problem or situation to occur again. 惡性循環

The more pesticides are used, the more resistant the insects become so the more pesticides have to be used. It's a vicious circle. 殺蟲劑使用得越多，那些崑蟲的觝抗力越強，因此就要使用更多的殺蟲劑。這是一個惡性循環。