作者：英吉
Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun's poles or equator,
(A) are visible as dark spots on the surface of the Sun but have never been sighted on
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(C) appear on the surface of the Sun as dark spots although never sighted at
(D) appear as dark spots on the surface of the Sun although never having been sighted at
(E) appear as dark spots on the Sun's surface, which have never been sighted on
题目分析：意思是说sunspots在什么地方是可以看到的，但是在什么地方是看不到的，A的意思是合理的。B那个that never 中的that指俄就是dark spots了，我要的意思是sunspot什么地方看得到什么地方看不到，不是dark spots什么地方看不到，杀。C也是dark spots看不到了，意思不对，杀。D前面用appear后面用having been sighted 前后不对应，杀。E那个which指代的又是dark spots了，和B选相犯的错误是一样的，干掉。
