问题补充:
An American scientist and writer coming to give us a lecture on English
learning methods when he visits our school.
A. was
B. were
C. is
D. are
答案:
A. was
B. were
(答案→)C. is
D. are
解析:考查时态及主谓一致。句意:当他参观我们学校时,一位美国科学家兼作业来给我们做一场关于英语学习方法的演讲。结合语境可知本句描述的是客观存在的事实,故用一般现在时态。联系下文可知科学家和作家指的是一个人,故谓语动词用单数,选C。