Question

4. —Would you like to come to my party on Saturday,Sam?

—I'd love to,   I can't. I have to take a piano lesson.

   A. and   B. but   C. or   D. so

Answer 1

4. B 考查连词辨析。由答语“我愿意去，但 我不能。我得去上钢琴课。”可知空格处前后 是转折关系，用转折连词but。