"Just a lucky guess," said the teacher.

“只是蒙对的而已，”老师说。

Emma: Have you never known the triumph of a lucky guess?

你就从来不知道猜个正着与成功的喜悦之后的区别么？

He didn't really know the answer — it was just a lucky guess.

他并非真知道答案——那不过是个侥幸的猜测。

He didn't really know the answer - it was just a lucky guess.

他并非真知道正确回答——那不过是个侥幸的猜测。

It was, but Cai Yong suspected that his daughter had just made a lucky guess.

确实是那样，但是蔡勇认为他女儿只是侥幸猜对了。