that用作代词

　　1.that用作指示代词（复数形式是those）,其指代意义同形容词用法,同时它还可以用作定语从句中的先行词；还可为了避免重复,代替前述名词.

　　Thatiswhathetoldme.

　　Whatisthat(which)youhavegotinyourhand?

　　Thepriceofriceishigherthanthatofflour.

　　2.that用作关系代词,引导限制性定语从句.先行词可人可物,用法相当于who或which.（但是在下列情况下多用that：先行词既有人又有物时；先行词有形容词最高级、序数词、不定代词、very,only等修饰时；先行词是不定代词时）

　　Hetalkedabouttheteachersandschoolsthathehadvisited.

　　Ithinkitoneofthemostwonderfulfilmsthatthefilmcompanyhaseverproduced.

　　Shehaslittleinformationthatisusefulforourresearch.

　　IsthereanythingthatIcandoforyou?

　　请注意,that在定语从句中作宾语时通常可省略.

　　Thebooks(that)Isentyouwillhelpyouinyourstudies.