As is recorded in history, silkworms（蚕）were first raised by a woman in is today Hebei Province．
A. where
B. the place
C. which
D. what
网友回答
A. where
B. the place
C. which
(答案→)D. what
解析：主要测试宾语从句。从句子的语境来看可知介词in需要宾语，同时句子 is today Hebei Province中有需要主语，另外结合答案可知只有what可以充当此双重作用，当然如果B后接that 或which也是正确的，但是那就变成了定语从句。