Is it the years when you worked in Africa as a doctor ___hav

Is it the years when you worked in Africa as a doctor ___have a great effect
a,where b,that
选b 是强调句吗.但是去掉Is it that.翻译下
have a great effect on your works you worked in Africa as a doctor in the years..
强调根本读不同啊！
我知道了。我一直搞错了。去掉Is it that。可以随便排。能通就可以了 that后面不一定是主语