第二部分选择填空(共20小题;每小题1分,满分20分)21.—Have you seen _______ pen? I left it here this morning.—Is it _______ black one? I think I saw it somewhere.
I have offered to paint the house ____ a week’s accommodation.
I can't say which wine is best -- it's a(n)of personal taste.
Please remainuntil the plane has come to a complete stop.
It’s the sort of work that ____ a high level of concentration.
worries me the way he keeps changing his mind.