请各位帮帮忙，告诉我你们的答案同时也附上解析。谢谢。
1，Do you have any idea _____ is actually going on in the classroom？
A、that B what C as D,which
2,It was a pity tht the great writer died ___ his work unfinished.
A for B with C from D of
3,____is no possibility ___ Bob can win the first prize in the match.
A There …that B It ...that C There...whrther
4,Don't___.You have another chance to have a try.
A be cast down B be lost heart C cast down
5,He was lucky enough to sell his car for excatly_____.
A where he had paid for it
B what he was paid for it
C what he had paid for it
D which he had paid for it

最好是有句子的解析。谢谢各位、

1.B
你知道教室里发生了什么事吗？
2.B
with 伴随壮语
令人遗憾的是，那位伟大的作家没有完成他的工作就去世了。
3.A
possibility 是名词，如果改为形容词--possible，就可用it is not possible
后半句是陈述，不表示疑问或不确定，所以需要使用that
鲍勃在这场比赛中不可能获得一等奖，这是不可能的。
4.A
不要沮丧，你还有机会来尝试一下。
表示“沮丧，灰心”的词语是“be cast down”“lose heart”
5.C
他很幸运能以购买价出售掉他的汽车。
for exactly 后面接表示价格的从句