vacillate

1. V-I If you vacillate between two alternatives or choices, you keep changing your mind. 犹豫不决[正式]

She vacillates between men twice her age and men younger than she. 她在两个男人之间摇摆不定，一个年龄比她大一倍，一个比她小。

We cannot vacillate on the question of the party's leadership. 在党的领导权问题上我们不能动摇。