1 . 我们反思自己过去的错误并下定决心不再犯。(汉译英)

2 . 她的病因尚不清楚，所以她被送到更好的医院。
The cause ________ ________ ________ was not clear, so she was sent to a better hospital.

3 . 我总是信守诺言，这一点对我十分有利。
It is a great advantage to me that I always ________.

4 . 他说,他先后两次访问中国,亲眼见证了这个国家的巨大变化。
He says that he has visited China twice and witnessed great changes of this country __________________________.