Until he told me yesterday,I knew______of what had happened to him .

—What do you think of these two books?—______ of them are interesting.And I’ve read them several times.

_______ is very important for us students to learn English well.

Legend has ______ that CaoCao, King of Wei kingdom in the Three Kingdoms period, built 72 tombs to confuse tomb diggers. 

—Which of those electronic dictionaries do you like most?—     .They are expensive and of little use.