-Good morning, Mr. Lee's office.
-Good morning. I'd like to make an appointment _________ next Wednesday afternoon.
for
on
in
at
Every evening after dinner, if not from work, I will spend some time walking my dog.
AIDS is said________the biggest challenge to both men and women in that area over the past few years.
The mobile phone has become a major means of communication, _____us to keep in touch as well as to surf the Internet to keep us _____of the latest news.
---What do you think of his talk on Information Technology?---Oh, excellent. It’s worth_____________.
I like getting up very early in summer. The morning air is so good______.