help的形容词形式和反义词是？

It is often helpful for teachers to shadow managers in industry.

教师跟随业界的管理人员实地学习，常常会很有收获。

I called the police but they weren't very helpful.

我叫了警察，但他们不太肯帮忙。

You'll find it helpful to talk things over with a friend.

把情况和朋友详细聊一聊，你会觉得大有帮助。

The waiters were rude and unhelpful, the manager ditto.

这些服务员态度生硬，服务不周，经理也一样。

It is unhelpful to extrapolate general trends from one case.

根据一个案例来推断总的趋势是没有用的。

People always complain that the big banks and big companies are unfriendly and unhelpful

人们总是抱怨大银行和大公司不友善、不愿提供帮助。