The research is so designed that once _____ nothing can be done to change it

It’s reported that Nanjing Metro Line 3 was in service __________ April 1,2015.—What _________ exciting news! I believe the public transport system of Nanjing will be much better.

“Well done, John！ Not a single mistake _____ in your exam paper this time！”said the teacher

Did you go toNancy’s birthday party last night —Yes.I did.

Elizabeth believed the dog would die if _____ to her cruel owners so she kept it