Mr. Brown is an experienced doctor. He is always _______ in facing with emergency.
---Do you know our town at all? ---No, this is the first time I ________ here.
We won’t give up _______ we should fail 10 times.
With the guide leading the way we were able to travel ___ the forest not ___ air but __foot.
Mother asked the youngest girl _________ with her toy car.
She still remembers Beijing University ______ she graduated five years ago.