A number of questions ________ by parents at the meeting, but the school leaders could not ________ any proper answer.

Remember to save what you ________ on once in a while in case the computer suddenly crashes.[ ]

It is thought that a new system _____ the place of the old one in that company. But things are getting worse and worse.

I wanted to see the Beijing Opera, so Lingling offered me to watch an opera.

Speaking of Utopia, a popular explanationis that it’s an ideal world, or a perfect final _________.