问题补充:
Mr.Smith is the only one of those foreigners who in China.
A. work
B. is working
C. are working
D. had working
答案:
A. work
(答案→)B. is working
C. are working
D. had working
解析:考查定语从句。本题定语从句的先行词是the only on,而不是those foreigners。关系代词who指代先行词the only one在句中做主语,后面使用单数的形式。句意:斯密斯先生是那些外国人中唯一的一个现在在中国工作的人。故B正确。D项的时态错误。