语法与词汇 20.His jokes seemed______, but were in fact carefully prepared beforehand.

【正确答案】 C

【答案解析】形容词形异义异辨析。spontaneous意为“自发的，自然发生的”，如：Hersuccess brought a spontaneous cheer from the crowd．她的成功使观众即时爆发出一阵欢呼声。