The April Fools' tradition is said ________ in the sixteenth century.
A.to start
B.to be starting
C.to be started
D.to have started
答案:D
D 考察非谓语动词及时态。句义:据说愚人节的传统开始于十六世纪,in the sixteenth century提示动作发生在过去,并对现在造成了影响,故使用完成式。Tradition与start之间构成主动关系,故使用不定式的完成式。故D正确。