1. Most people agree that knowledge of ___ nation’s culture is __ must in trade or communication.
A. the; / B. /; the C. /; a D. a; a
2. —I’d like a pen which well.
—Will this one_______?
A. writes; do B. writes; work C. is written; do D. is written; work
3. By the time you _______in London, we will have stayed in Europe for two weeks.
A. will arrive B. arrived
C. arrive D. have been arriving
