Peter __________ come with us tonight, but he isn’t very sure yet.

accepted the job becausehe likes challenge, and the chance of dealing with difficult problems ____ tohim

The reason why she couldn’t come to the meeting was_____ she had not been invited

clear Security Summit is an initiative of Mr. Obama, considers nuclear terrorism to be one of the greatest threats to international security.

go there by ____train ,you can have quite acomfortable journey ,but make sure you get ___fast one.