Have you heard of Zhai Mo ______became the 

问题补充：

HaveyouheardofZhaiMo______becamethefirstChinesepersontotravelaroundtheworldinasailboat?A.thatB.whoseC.whichD.whom

答案：

A解析考查定语从句。先行词是Zhai Mo，在定从______became the first Chinese person to travel around the world in a sailboat中作主语，所以选A。