In the office I never seem to have time until afer 5:30 p.m , ____many people have gone home.
A.whose time B.that
C.on which D.by which time
为什么选D,不选C


We want such materials ____ can bear high temperature and pressure.
A.that B.as
C.what D.which
为什么选B.不选D


All ___ is a comtinuous supply of the basic neceesities of life.
A.is needed B.for our need
C.which is needed D.that is needed
为什么选D.不选C??

1.到5点半后，许多人回家的时候，我才有空
by which time ,=by the time of 5:30 p.m,这是非限制性定语从句,到什么时候要用介词by,而which time 指的是the time of 5:30 p.m根据后面的时态have gone home,选择介词by
2. B.as 引导定语从句,虽然先行词是materials,但是它的前面有 such 翻译:我们需要诸如能够承受高温和压力的材料.
3.All是不定代词,后面要求用that引导定语从句,在定语从句中,先行词是all ,some ,any ,等不定代词及最高级时，用that不用which，例如：I've done all that can be done.
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