The business is risky.But_,we would be rich. A.

1. The business is risky.But_,we would be rich. A.

道题的答案是A 
这是一个倒装句，而且是虚拟条件句的倒装,可以形成这种倒装的有三个词should, were和had 
下面先举一个were的例子,中文:要是我是你的话,我不会那样做. 用正常语序应当是 If i were you, I would not do it. 这种句子一旦倒装的话,就要省去if,于是上句就变成 Were I you, I would not do it. 再举一个had 的例子: Had I come earlier, I would have seen her. 中文为我要是早到点就见到她了. 
那题目中的句子正常语序应当是But if we should succeed那一旦倒装就是A 答案的语序了.意思是这个生意是有风险, 但是我们要是能成功的话,我们就发财了. 
所以只能选A 而其他几个词would might could 都不能用在倒装虚拟条件句中.