【C6】A．thisB．thatC．whichD．whose

A．thisB．thatC．itD．these

A．thisB．thatC．nothingD．anything

【C17】A．thisB．thatC．itD．so

【C4】A．whatB．thatC．whichD．where

【C19】A．thisB．thatC．／D．what

【C7】A．thisB．thatC．itD．such