（ ）dark it is,she still went to the classroom.a though b as c however d but答案是c汗颜..我忘记问了 为什么选c 让不行状语的连词 不也可以用a么 用cdscdma 的观点排除a 是正确的么？

however
[hau?ev?]
adv.
不管到什么程度, 无论如何
I'll come however busy I am.
我不管怎么忙都会来的。
然而, 可是, 不过
Later, however, he made up his mind to go.
可是, 后来他决定去了。
conj.
不管怎样
But I am very much believable, however, you'll get him to come.
我相信你不管怎样都能把他请来。
不论天多黑，她还是去上课了。

C的意思是然而
这里根据上下文，其实有无论的意思
无论有多黑暗，她还是回到了教室。
用a就必须是
though it is dark，。。。。。。

though it is dark

无论多黑 她仍旧去教室

a 虽然天很黑她仍走去班级

不论天多黑，她还是去上课了。
however 修饰dart 是副词

选a 应该是though it is dark
b 是 dark as it is
选c however 这里等于no matter how
d 我相信你第一个就会排除的

根据句意 无论多黑 她仍旧去教室
只有 however 有这个意思