The lecture was so______that everyone went to sleep.
【正确答案】 A
【答案解析】解析:本题考查形容词词义辨析。A项“枯燥的”,多形容物;B项“无聊的”,多形容人;C项“有趣的”;D项“有兴趣的”。代入题干,A项最符合题意,故选A。