He is ill. I don’t know _______ he will come to school.
If we travel a short distance, we should walk _____ taking a bus. Then we’ll be greener people.
The boy found __________ hard to get along with the other classmates.
--- –Could you please __________ the window? It’s cold outside.--Sorry, I won’t.
----Bob, have you ever heard of the latest iPhone?----Yes, of course, but I haven’t decided whether to buy_________.
Which two of the following words have the same pronunciation for its underlined part?“ a. upon b. opinion c. completely d. stone”