21. ____ walk is expected to last all day, so bring ____ packed lunch.
A. A; a B. The; 不填 C. The ; a D. A ; 不填
22. Cao Cao’s tomb is reported ______ in China, which attracts nationwide attention.
A.being found B.to be found
C.having been found D.to have been found
23.I would rather buy a house in the countryside than ______ in the city.
A.it B.one C.this D.that
