More and more teaching _______ are being developed across the globe, which are sure to _______to make classroom teaching more lively and interesting. [ ]

Excuse me， do you have an English dictionary— No， but Mr Zhang has one. Please ________ him for it.

This kind of CD-ROM is very popular. Whynot buy one before it___________

How is Helen in the new school— She is doing very well. There is ____ to worry about(担心).

She agreed us, so we agreed the project at last