连...都

连...也

If the two patterns above used in a sentence, the speaker expresses his surprise, and the result is unexpected..

连我都知道了，你怎么还不知道啊？means "Even I know this, why don't you know?". It's normal that you know the matters first, or before me, but this time I get the news befor you, so I felt surprised and unexpected.

他太善良了，连苍蝇都不敢打死。 We all think that killing a fly is easy and not guilty. However, for him, it's impossible, so the speaker felt surprised and unexpected.

In the sentences above, the meaning won't be changed if "也" instead of "都", but we always use "都".