Mary is the only one of the students in our class who ____ to the Great Wall so far.
As _____ matter of fact, basic gardening is so easy to achieve that even people with physical handicaps can garden.
They travelled around _____ Changchun by _____ bus.
John rushed out in a hurry, _____ the door _____ .
Please come to visit me if _________________.
---Why do you look so sad? ---There are so many problems_______.