ineffective
adj
not producing the required effect(s) 不起作用的; 無效果的; 效果不佳的
use ineffective methods 使用無效的方法
She is totally ineffective as a teacher, ie She cannot teach satisfactorily. 她當老師全然不稱職.
??? 情景例句
they insisted that I stay.
他們堅持要我留下來。
What sort of guarantee do you offer on your product?