They periodically stopped their conversations to switch tables so the insights and ideas might 13 and deepen.
答案：(A) circulate
circulate 是「流通、傳布」，本句指與會者換桌讓見解與想法得以流通並深化；emphasize（強調）、recover（恢復）、preserve（保存）語意都不合。
circulate 你大概只記得「血液循環」（Blood circulates through the body. 血液在體內循環）。用在消息、想法、文件上時，它的意思是「流通、傳開」：Rumors circulated quickly.（謠言很快傳開）。
空格與 deepen 由 and 並列、同受 might 支配，可知要填的是與 deepen 同類的不及物動詞，且語意上與「加深」互補。前半句 They periodically stopped their conversations to switch tables（他們不時中斷談話、換到別桌）說明了機制：人換桌，見解與想法也隨之傳到別桌，正是「流通」。後一句 As they moved from one table to another, they noticed new ideas emerging from the discussions.（他們從一桌換到另一桌時，注意到討論中不斷湧現新想法）再次印證。circulate 就廣度而言、deepen 就深度而言，兩者並列而語意互補。凡是空格與另一個動詞由 and 並列的題目，判斷步驟相同：先確認並列成分的詞性與及物性，再從語意是否互補來挑選。
emphasize（強調）與 preserve（保存）都是及物動詞，須接受詞，本句空格後直接接 and deepen，句型即不成立。recover 是「恢復、復原」，用於健康、損失或失物，而見解與想法並未失去，語意不合。
circulate（流通、傳開）、circulation（發行量、循環）、rumors circulate（謠言流傳）、circulate a memo（傳閱備忘錄）、deepen one's understanding（加深理解）。
In 1995, a group of business and academic leaders met at the home of Juanita Brown and David Isaacs in Mill Valley, California. None of them had any idea they were about to create a social innovation that 11 rapidly around the world.
The group was supposed to have a large-circle discussion in their beautiful garden. Unfortunately, it started pouring. With their plan 12 by the rain, the two dozen participants squeezed into the living room. They broke into small, intimate table conversations, recording their insights on paper tablecloths. They periodically stopped their conversations to switch tables so the insights and ideas might 13 and deepen. As they moved from one table to another, they noticed new ideas emerging from the discussions. This in turn enriched subsequent rounds of conversation.
Over the course of the morning, the innovative discussion process 14 a new form of collective effort that transformed the depth, scope, and quality of their discussion. The World Café was 15 created. Since that rainy morning in Mill Valley, the World Café approach has been applied to multi-group discussions and cooperative actions by businesses, industries, and educational institutions around the world.