在黄og11-9中 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) Sun's poles or equator.
D) appear as dark spots on the surface of the Sun, although never having been sighted at
为何og对d的解释中说到”although typically introduces a subordinate clause, which has a subject and a verb, but here there is no subject and sighted is not a complete verb"
可是在黄og11-29中，题目里： Along with the drop in producer prices announced yesterday, the strong retail sales figures released today seem (like it is indicative that) the economy, although growing slowly, is not nearing a recession. 在这里未划线处，它自己却用了although＋现在分词结构的形式。 请问“”although typically introduces a subordinate clause”这个结论是不是只是一条很弱的判错标准呢？还是我的理解有误？
