Naval requirements are now being considered and could produce orders for six or seven vessels, including frigates, during the next three to four years.
A、invest in
B、book in
C、place in
D、result in
【正确答案】：D
【名师解析】:选项D "result in" 是正确答案，因为它意味着海军需求的考虑可能会导致在未来三到四年内下达六到七艘舰艇的订单。这里的 "produce" 与 "result in" 意思相近，都表示某种情况或行为最终导致某种结果或后果。其他选项A "invest in"（投资于）、选项B "book in"（预定）、选项C "place in"（放置在）都不符合句子的语境。
