One should keep ________ promise

Theresearchonthenewbirdfluvirusvaccmeischallenginganddemanding.Whodoyouthink candothejob?— _____ mystudentshaveatry?[ ]

We talked untilMr wu asked us

He made a promise __________he would help me.

iang’s breaking the world record was an exciting moment, ______ all of us will never forget.