1.Isthislaboratory______thestudentsvisitedyesterday改为它的陈述语序是

　　Thislaboratoryis______thestudentsvisitedyesterday

　　2.Isthisthelaboratory______thestudentsvisitedyesterday改为它的陈述语序是

　　Thisisthelaboratory______thestudentsvisitedyesterday

　　.所以1.B,theone（作表语）,(thestudentsvisited）是定语从句,修饰theone

　　由于theone作visited的宾语,所以theone后省略了that或which.

　　2.A,that(它引导定语从句),修饰先行词thelaboratory,visited的宾语是that,所以that可省略

　　由于visited是及物动词,所以不可能出现介词in,所以inwhich不对

　　visittoaplace这句话中，towhich=where

　　当visit用作及物动词时，后面不加to当visit用作名词时payavisittoaplace中towhich(which代替place)=where如Thisistheplacewherewepaidavisitlastyear.