“咬牙坚持”用英语可以表示为“grind one's teeth and persist”或“bite the bullet and persist”。

“咬牙坚持”这个词组来源于军事术语，在战时医疗中，士兵需要在手术过程中“咬紧牙关”来减少疼痛。这种做法被用来比喻在困难和痛苦中坚持前进。

例句：

He had to grind his teeth and persist through the difficult project.
She had to bite the bullet and persist through the difficult situation.
Despite the challenges, he was determined to grind his teeth and persist.
She knew it wouldn't be easy, but she was prepared to bite the bullet and persist.

其中文翻译分别为:

他不得不咬紧牙关，坚持完成这个困难的项目。
她不得不咬紧牙关，坚持度过困难的时刻。
尽管有很多困难，他还是决心咬牙坚持。
她知道这不容易，但她还是准备好咬牙坚持了。