题目

Scientists had (寻找) for a solution to the mystery, but they didn't find it. 答案：【1】sought/searched鸦片战争后，清政府被迫与美国签订的不平等条约是A.《虎门条约》B.《黄埔条约》C.《尼布楚条约》D.《望厦条约》