He was so____ a key university that he would work until late into the night.
Perhaps the day will come ____ people will be able to breathe clean air in cities.
Modern forms of transportation and communication have done much to ______ the isolation(隔离)of life in Alaska.
I can ________ the house being untidy, but I hate it if it’s not clean.
_________ Kunming you see today is quite _____ different city from what it used to be. A.The, 不填 B.不填, a C.The, a D.A.a
Sir, do you have anything _________ this afternoon? If there is nothing to do, I wonder if I can ask for a leave.