society full of challenges and opportunities, in my opinion, it is a must to have a good ______ of a foreign language.

Whose model plane is it—It’s Jack’s. He made it by _______.

I would appreciate _____, to be frank, if goods could be delivered as soon as possible. [ ]

Sandy does not have much time to play tennis. She_____ plays tennis.

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