【问】 enquire of(亦作inquire of)与enquire about，enquire after和enquire at有何区别?
 【答】 enquire of sb.是指“向某人打听”、“询问某人”：
 1. I enquired of him the way to Chicago. (Davis)
 我问他去芝加哥的路。
 2. I have enquired of the city planners...(LDPV)
 我已询问了城市规划人员……
 enquire about是“询问关于……的情况”：
 He went to enquire about the times of trains to Edinburgh. (EED)
 他去询问去爱丁堡的火车的时间。
 enquire after是指“打听关于……的情况”、“问侯”：
 My mother enquired after you.
 我妈妈向你问好。
 enquire at表示“在……地方打听”：
 I'll enquire at the office and then tell you the time.
 我去办公室问问，然后把时间告诉你。
 enquire for是指“找某人”，“问……在什么地方”：
 A young man enquired for you when you were out.
 你外出时有一位青年来找你。
 请做下面的英语试题：
 “Did you inquire about work permits?”
 “Yes. They are available________. ”
 A. upon request B. if asked
 C. for their requesting D. when asking for them. (TOEFL，75. 9)