问题
选择题
______ has Miss Green taught in your school? For about six years.
A. How long B. How soon C. How far
答案
答案：A
题目分析: 句意：格林老师在你们学校教多久了？大约六年。How long多久，用于现在完成时，How soon 多久，用于一般将来时，How far多远。根据has taught可知为现在完成时，故选A.