What was the mood of the researchers to discover this phenomenon?

(单选题)______ on the top of the mountain, and you’ll get a good bir (单选题)The top leaders of the two countries are holding talks in a (单选题)Since the matter was extremely ______, we dealt with it imme (单选题)We thought there were 35 students in the dining hall, ______ (单选题)______ we have a vast land and still a lot of mineral resour (单选题)His ______ voice shows that he’s greatly ______. (单选题)A month had passed, but the government didn’t find the _____ (单选题)Great ______ have been made to make our environment more and (单选题)The patient recovered from the illness ______ and three week (单选题)We can surely overcome these difficulties as long as we are