There were _ interesting books there_we didn't know which we

There were _ interesting books there_we didn't know which we I had to buy __of the books because I didn't know which one 1、I had to buy _____ these books because I didn't know which There are too many books,i don`t know which还是which one to ch There are so many interesting books here.I really don't know didn't know you were so busy. 英语句子改错：I didn't know why you were so busy in the last there There are many Christmas cards____but I didn't know which on We were shocked to find that Mary didn't know her guest's na 请问we were shocked to find that Mary didn't know her guest's there were many interesting books in the library tomorrow改写 He didn't know which hat was his.还是应该用：He didn't know which