He didn’t know _______ next, so he asked his teacher for help.

The hotel is almost finished, but it _____ needs one or two weeks to get ready for guests

We can use QQ to communicate with eachother online. —Good. Will you please show me

The television is a _____ machine.

Some people hold the view that the new machine isadvanced, while others are still skeptical _____ whether it is of practicaluse.