When Zhao Benshan appeared on the stage, people______laughter. [ ]

The question of drug-taking is bound to(一定要) ______ at the next conference.

________ makes mistakes must correct them

I need to advertise for a second-hand mountainbike— _______David just plans to sell his present one

Thanks a lot for offering a great deal of _______ to me in my research.— It was my great pleasure.