【C9】A．whichB．whomC．whatD．who

This is the book（)I have learned a lot.A. to whichB. by whomC. from which

A．whichB．whomC．whoD．what

【C6】A．whichB．whereC．whatD．when

A．whoB．whomC．whatD．which

【C8】A．whichB．thatC．whatD．when

【C5】A．whichB．thatC．whatD．than