In April, 2009, President Hu inspected the warships in Qingdao, ______ the 60th anniversary of the founding of the PLA Navy.

Gun control is a subject ______ Americans have argued for a long time.

Distinguished guests and friends, welcome to our school, _____the ceremony of the 50th Anniversary this morning are our alumni （校友） from home and abroad.

When we visited my old family home, memory came ______ back 

_____ by the advances in technology, many farmers have set up wind farms on their land.

______ the project in time, the staff were working at weekends.

Ladies and gentlemen, please remain __________ until the plane has come to a complete stop.

He told us whether _________ a picnic was still under discussion

____ twice, the postman refused to deliver our letters unless we changed our dog

All of them try to use the power of the workstation ___ information in a more effective way.