问题
选择题
I have been living in the United States for twenty years ,but seldom _____ so lonely as now.
A．have I felt
B．I had felt
C．I have felt
D．had I felt
答案
答案：A
句意：我在美国已经住了20年了，但很少像现在这样孤独。由seldom 可知需要使用部分倒装结构，同时我们不难判断应使用现在时态。
