【C6】A．ItB．WhatC．ThatD．There

【C4】A．whichB．whatC．thatD．it

A．whichB．whatC．thatD．those

【C12】A．whichB．whatC．thatD．it

【C18】A．itB．whichC．thatD．him

【C13】A．whenB．whatC．thatD．if

【C8】A．whichB．whatC．thatD．who