Seldom__my boss in such good mood since I came to work in this companyA I saw B I have been C have I seen D do I see

问题描述:

Seldom__my boss in such good mood since I came to work in this company
A I saw B I have been C have I seen D do I see

Seldom置句前,需用倒装句!
加上本句中有since表示时间段
所以应该选C Have I seen