18. A new ___ bus service to Tianjin Airport started to operate two months ago .
At the age of 29, Dave was a worker, _____ in a small apartment near Boston and ______ what to do about his future.
I can ______ be a teacher. I’m not a very patient person.
When he _______ the door, he found his keys were nowhere.
Most Americans would prefer to keep their problems ______ themselves, and solve their problems ______ themselves.
Every evening after dinner, if notfrom work, I will spend some time walking my dog.