It is strange that the well-behaved gentleman be so rude.
A. should
B. need
C. might
D. would
网友回答
(答案→)A. should
B. need
C. might
D. would
解析：句意：真是非常奇怪彬彬有礼的这位绅士竟然如此地粗鲁。这里是固定句式，在句型 It is important (necessary, strange, impossible, natural) that .... 中，that后面的从句中的谓语动词用：(should) + 动词原形。这里是虚拟语气中的一种情况，故选A。