His lecture was difficult and I didn’t know ________ he said meant in his lecture．
A.thatB.whatC.that thatD.what what在线课程D
解析：
第一个what作动词meant的宾语，第二个what作动词said的宾语，即在I didn’t know what what he said meant in his lecture中，I didn’t know为主句，what what he said meant in his lecture为宾语从句，而在此宾语从句中又包括有what he said这样一个主语从句。