题目

Being overweight i_________ the risk of having a heart problem. You’d better exercise more. 答案：(i)ncreases【详解】 句意：超重会增加患心脏病的风险。你最好多锻炼。分析 “Being overweight i…the risk of having a heart problem.”可知，此处表示 “ 增加 ” ，可用 increase 表示，时态是一般现在时，主语是 Being overweight ，动词用三单，故填 (i)ncreases 。若2x=-y，则xyx2-y2=2323．