en_tn/luk/01/34.md

How will this happen

This could be translated as "How is this possible?" Though Mary did not understand how it could happen, she did not doubt that it would happen.

will come over you

This phrase and the next one are ways of saying that the Holy Spirit would supernaturally cause Mary to become pregnant even while she still remained a virgin. Make sure it is clear that there was no physical union involved; this was a miracle.

The power of

This could be translated as "By his power."

will overshadow you

This could be translated as "will cover you like a shadow" or "will be with you" or, "will cause this to happen." Again, make sure this does not imply any physical union.

the holy one

"the holy child" or "the holy baby"

will be called

This could be translated as "people will call him" or "people will acknowledge that he is."